Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
CORD TENSION CONTROL FOR TOP DOWN/BOTTOM UP COVERING FOR
ARCHITECTURAL OPENINGS
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates generally to top down/bottom up
coverings
for architectural openings and more particularly to a system for preventing
entanglement
of lift cords used in such coverings for raising and lowering horizontal rails
in the
covering between extended and retracted positions.
Description of the Relevant Art
[0002] Retractable coverings for architectural openings have been in use
for
many years. Early forms of such retractable coverings were referred to as
Venetian
blinds wherein a plurality of horizontally disposed, vertically spaceable
slats are
supported on cord ladders and utilize a control system that allows the slats
to be raised
or lowered to move the covering between retracted and extended positions
relative to the
architectural opening in which the covering is mounted. The slats can also be
tilted
about horizontal longitudinal axes to move the covering between open and
closed
positions.
[0003] More recently, cellular shades have been developed wherein
horizontally
or vertically disposed cells that are transversely collapsible, extend between
horizontal or
vertical rails, respectively, so that by moving the rails toward or away from
each other,
the covering can be retracted or extended across the architectural opening.
[0004] Retractable coverings utilizing horizontal rails for extending
and retracting
the covering usually employ lift cord systems for raising or lowering one or
more rails to
effect extension or retraction of collapsible shade material that
interconnects the rails. In
early retractable coverings or shades, one edge of the collapsible shade
material would
be secured to a headrail that also included a control system for the covering
while the
opposite edge of the shade material was connected to a movable bottom rail
which could
be raised or lowered by the control system to retract or extend the covering,
respectively.
In other words, by lifting the lower rail toward the headrail, the shade
material would
collapse therebetween until the covering was fully retracted. By lowering the
bottom rail,
the shade material would extend across the architectural opening.
[0005] As an evolution of such retractable shades, top down/bottom up
coverings
have been developed, which typically include a headrail, a movable top rail
and a
movable bottom rail with a shade material extending between the top and bottom
rails.
The control system for such coverings utilize sets of lift cords which can
independently
CA 02797850 2016-05-10
raise or lower the top and bottom rail so that the covering becomes a top down
covering
by lowering the top rail toward the bottom rail, or a bottom up covering by
raising the
bottom rail toward the top rail. Further, the rails can be positioned at any
elevation within
the architectural opening and with any selected spacing between the top and
bottom rails
for variety in positioning of the shade material across the architectural
opening.
[0006] The problem encountered with such retractable coverings resides
in the
fact that the lift cords themselves are typically wrapped around spools within
the headrail
and when one movable rail is moved past a position occupied by another movable
rail,
the lift cords sometimes become entangled on their associated spools causing
malfunctioning of the covering. While efforts have been made to avoid such
entanglement, efforts are still being made to deal with this problem, and the
present
invention has been developed as a remedy.
SUMMARY OF THE INVENTION
[0007] A cord tension control system pursuant to the present invention
has been
designed to avoid entanglement of lift cords about their wrap spools within a
headrail of a
retractable covering of the top down/bottom up type. The invention addresses
the
problem by providing pairs of adjacent threaded rods adapted to rotate in
unison with
wrap spools with which they are associated and with the wrap spools further
being
associated with a particular rail to which collapsible shade material is
attached. As a rail
is raised or lowered with an associated lift cord, thus effecting rotation of
a cord spool
and the wrapping of a lift cord thereabout, a threaded shaft rotates in unison
therewith
and includes an abutment nut which translates along the length of the threaded
shaft as
it rotates. Pairs of the threaded shafts, with one shaft of each pair being
associated with
each rail, are closely enough positioned so that the abutment nuts on each
shaft will
engage each other at preselected positions of the nuts so that movement of one
rail past
another can be avoided at any desired relative location of the rails thus
avoiding
entanglement of the lift cords associated with each wrap spool.
According to one aspect of the invention there is provided a covering for an
architectural opening comprising in combination:
a headrail;
at least two horizontally disposed vertically movable rails supporting at
least
one panel of collapsible shade material;
at least two flexible lift cords affixed to each rail;
a control system component associated with each rail, each component
including an elongated drive shaft, a system for reciprocally and reversibly
rotating said
drive shaft about its longitudinal axis, a wrap spool rotatable with said
drive shaft and
2
CA 02797850 2016-05-10
Ps
connected to a lift cord such that said lift cord can be wrapped about or
unwrapped from
said wrap spool, vertical movement of said rails being effected by wrapping
and
unwrapping of said lift cords about said spools, and
a cord tension control system for preventing said lift cords from becoming
entangled at said wrap spools, said cord tension control system including a
threaded shaft
associated with and rotatable in unison with each drive shaft, a nut threaded
on each of
said threaded shafts for translating movement along an associated shaft, the
nuts on said
threaded shafts overlapping in their path of travel along an associated
threaded shaft
whereby upon engagement of said nuts with an adjacent nut the drive shafts
will be
prohibited from rotating in a predetermined direction thereby prohibiting the
wrap spools
on said drive shafts from rotating;
said cord tension control system further including a housing in which said
threaded shafts are rotatably mounted, fixed abutments in said housing in
engagement
with said threaded shafts to prevent a predetermined amount of axial movement
of said
shafts in a predetermined direction and resilient members in said housing
biasing each of
said shafts against said fixed abutments, said housing further having side
walls and a
bottom wall with said resilient members being mounted on said bottom wall.
[0008] Other aspects, features and details of the present
invention can be more
completely understood by reference to the following detailed description of
the preferred
embodiments, taken in conjunction with the drawings and from the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
00091 FIG. 1 is an isometric of a top down/bottom up covering
shown in a fully-
extended condition and incorporating the cord tension control system of the
present
invention.
2a
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
[0010] FIG. 2 is an isometric similar to FIG. 1 with a top rail of the
covering
having been lowered.
[0011] FIG. 3A is an exploded isometric of the headrail and control
system used
in the covering of FIGS. 1 and 2.
[0012] FIG. 3B is an exploded isometric showing the top and bottom rails
and the
collapsible fabric extending therebetween of the covering shown in FIGS. 1 and
2.
[0013] FIG. 4 is an isometric with parts removed showing the
components of the
covering illustrated in FIGS. 3A and 3B.
[0014] FIG. 5A is a front elevation of the covering of FIGS. 1 and 2
positioned
within an architectural opening and in the fully-extended position of FIG. 1
with the top
rail adjacent the headrail, and the bottom rail adjacent the bottom of the
architectural
opening.
[0015] FIG. 5B is a front elevation similar to FIG. 5A with the top
rail having been
lowered while maintaining the bottom rail adjacent the bottom of the
architectural
opening.
[0016] FIG. 5C is a front elevation similar to FIG. 5B with the bottom
rail having
been raised into closely spaced relationship with the lowered top rail.
[0017] FIG. 5D is a front elevation similar to FIG. 5A with the bottom
rail having
been raised fully to place the covering in a fully retracted condition.
[0018] FIG. 6 is an enlarged fragmentary view taken along line 6-6 of FIG.
4.
[0019] FIG. 7 is a top isometric with parts removed of the open topped
housing
component of the cord tension control system of the invention.
[0020] FIG. 8 is a section taken along line 8-8 of FIG. 6.
[0021] FIG. 9 is a section taken along line 9-9 of FIG. 6.
[0022] FIG. 10 is a section taken along line 10-10 of FIG. 6.
[0023] FIG. 11 is a section taken along line 11-11 of FIG. 6.
[0024] FIG. 12 is a front isometric looking downwardly on an abutment
nut used
in the cord tension system of the invention.
[0025] FIG. 13 is a rear isometric looking downwardly on the abutment
nut of the
cord tension system of the invention.
[0026] FIG. 14 is an isometric looking downwardly at the enlarged end
of a
threaded shaft component of the cord tension control system.
[0027] FIG. 15 is an isometric looking downwardly on the small end of
the
threaded shaft of the cord tension control system.
3
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
[0028] FIG. 16A is a top plan view looking downwardly on the cord
tension
control system of the invention showing the abutment nuts in the positions
they would
when the covering is disposed as shown in FIG. 5A.
[0029] FIG. 16B is a top plan view showing the abutment nuts in the
position they
would assume when the covering is in the condition of FIG. 5B.
[0030] FIG. 16C is a top plan view of the cord tension control system
with the
abutment nuts assuming the position they would be in with the covering in the
position
illustrated in FIG. 5C.
[0031] FIG. 16D is a top plan view showing the abutment nuts assuming
the
position in which they would be when the covering is in the condition
illustrated in FIG.
50.
[0032] FIG. 17A is an isometric of a second embodiment of a
retractable
covering shown in a fully-extended condition and incorporating a second
embodiment of
the cord tensioning system of the present invention.
[0033] FIG. 17B is an enlarged isometric with portions removed showing the
covering of FIG. 17A.
[0034] FIG. 18 is an isometric similar to FIG. 17A with the top rail
being fully
raised and the middle rail being fully lowered to place the covering in a
fully retracted
position.
[0035] FIG. 19A is an exploded isometric of the headrail and the control
system
confined within the headrail for the covering illustrated in FIG. 17A.
[0036] FIG. 19B is an exploded isometric with parts moved
illustrating the upper
shade panel and the middle rail of the covering of FIG. 17A.
[0037] FIG. 190 is an exploded isometric showing the middle rail,
lower shade
panel, and the bottom rail of the covering of FIG. 17A.
[0038] FIG. 20 is an isometric with parts removed showing the control
system for
the covering of FIG. 17A along with the top, middle, and bottom rails of the
covering.
[0039] FIG. 21A is a front elevation showing the covering of FIG. 17A
fully
extended and in an architectural opening.
[0040] FIG. 21B is a front elevation similar to FIG. 21A showing the top
rail
having been partially raised, and the middle rail partially lowered.
[0041] FIG. 210 is a front elevation of the covering of FIG. 17A
showing the top
rail having been fully raised, and the middle rail raised into contiguous
relationship with
the top rail.
4
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
[0042] FIG. 21D is a front elevation of the covering of FIG. 17A
showing the
middle rail having been fully lowered, and the top rail having been lowered
into
contiguous relationship with the middle rail.
[0043] FIG. 21E is a front elevation of the covering of FIG. 17A
showing the top
rail having been fully raised, and the middle rail fully lowered.
[0044] FIG. 22 is an enlarged fragmentary view taken along line 22-22
of FIG.
20.
[0045] FIG. 23 is a front elevation of the cord tension control unit
shown in FIG.
22.
[0046] FIG. 24 is a section taken along line 24-24 of FIG. 22.
[0047] FIG. 25 is a section taken along line 25-25 of FIG. 22.
[0048] FIG. 26 is a section taken along line 26-26 of FIG. 22.
[0049] FIG. 27 is a top isometric with parts removed of the open
topped housing
for the cord tension control system shown in FIG. 22.
[0050] FIG. 28 is an isometric looking downwardly at the enlarged end of a
threaded shaft used in the cord tension control system shown in FIG. 22.
[0051] FIG. 29 is an isometric looking downwardly at the small end of
the shaft
shown in FIG. 28.
[0052] FIG. 30A is a top plan view of the cord tension control system
shown in
FIG. 22 with the abutment nuts positioned where they would be when the
covering was
in the position of FIG. 21A.
[0053] FIG. 30B is a top plan view of the cord tension control system
of FIG. 22
with the abutment nuts positioned where they would be with the covering in the
position
of FIG. 21B.
[0054] FIG. 30C is a top plan view of the cord tension control system shown
in
FIG. 22 with the abutment nuts in the position in which they would be with the
covering in
the position of FIG. 21C.
[0055] FIG. 30D is a top plan view of the cord tension control system
of FIG. 22
with the abutment nuts in the position they would assume with the covering in
the
position of FIG. 21D.
[0056] FIG. 30E is a top plan view of the cord tension control system
shown in
FIG. 22 with the abutment nuts in the position they would assume with the
covering in
the position of FIG. 21E.
[0057] FIG. 31 is an isometric with parts removed of a open topped
housing for a
third embodiment of the cord tension control system of the invention.
5
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
[0058] FIG. 32 is an isometric looking downwardly at the enlarged end
of a
threaded shaft used in the cord tension control system of the third
embodiment.
[0059] FIG. 33 is an isometric similar to FIG. 32 looking downwardly
at the
opposite end of the threaded shaft.
[0060] FIG. 34 is a top plan view looking downwardly into the open-topped
housing with a pair of the threaded shafts seated therein.
[0061] FIG. 35 is a front elevation of the control system as shown in
FIG. 34.
[0062] FIG. 36 is a top plan view similar to FIG. 34 showing the
abutment nuts in
abutting relationship.
[0063] FIG. 37 is a top plan view similar to FIG. 36 showing the abutment
nuts
separated from each other.
[0064] FIG. 38 is a fragmentary vertical section taken along line 38-
38 of FIG. 37
showing the abutment nut of the lower shaft as viewed in FIG. 37 in dashed
lines.
[0065] FIG. 39 is a fragmentary vertical section taken along line 39-
39 of FIG. 36
showing the abutment nut of the bottom shaft as viewed in FIG. 36 in dashed
lines.
[0066] FIG. 40 is an enlarged fragmentary section taken along line 40-
40 of FIG.
39.
DETAILED DESCRIPTION OF THE INVENTION
[0067] FIGS. 1-16D illustrate an arrangement of a top down/bottom up
covering 40 for use in an architectural opening 42 (FIGS. 5A-5D) wherein the
covering
incorporates the first embodiment 64 of a cord tensioning system in accordance
with the
present invention. As best seen in FIGS. 1-4, the top down/bottom up covering
has a
headrail 46, a top rail 48, a bottom rail 50, a collapsible shade material 52
positioned
between and interconnecting the top rail and the bottom rail, and a control
system 54 for
independently raising and lowering the top rail and bottom rail. While the
shade material
could be any transversely collapsible material, it is illustrated for purposes
of the
disclosure as a panel comprised of a plurality of horizontally extending,
longitudinally
connected cells 56, which are transversely collapsible so that the panel can
be fully
extended as shown in FIG. 1 or fully retracted as shown in FIG. 2. Atop edge
58 of the
panel or shade material is secured along its length to the bottom surface of
the top rail in
any conventional manner such as with the use of an anchor strip 60 (FIG. 3B),
positioned within the uppermost cell, and trapped within a channel (not seen)
provided in
the lower surface of the top rail. Similarly, the lowermost cell in the panel
is attached to
the top surface of the bottom rail with an anchor strip 62 insertable through
the
lowermost cell and trapped within a channel in the top surface of the bottom
rail. In this
6
manner, relative movement of the top rail and bottom rail, away from or toward
each
other, causes the panel of shade material to be expanded or retracted,
respectively.
100681 The top 48 and bottom 50 rails of the covering are raised
and lowered
while remaining horizontally disposed and parallel with each other by the
control
system 54 seen best in FIGS. 3A and 4. As will be appreciated with the
description that
follows, the control system includes two identical components 54A and MB,
which are
reversed within the headrail, with one component 54B raising and lowering the
top rail 48
and the other 54A the bottom rail 50. For purposes of simplicity, only one of
those
components 54A will be described in detail. The tension control system 64 of
the
present invention integrates the two components MA and MB of the control
system in a
manner to be described hereafter to provide a positive control system, which
prevents
entanglement of lift cords 90 which form a part of each component of the
control system.
100691 With reference to FIG. 3A, the control system component 54A
shown to
the left or above the other component will be described and can be seen to
include an
elongated horizontally disposed drive shaft 68 of non-circular cross-section
which
extends substantially from one end cap 70 of the headrail to an opposite end
cap 72. At
the left end cap 70, a drive pulley 74 is provided having a circumferential
channel defined
by a plurality of radially extending gripping teeth 76 so that an endless
control cord 78
positioned within the channel can rotate the drive pulley in either direction
by circulating
the control cord in one direction or the other. The control cord has a tassel
80
incorporated therein to facilitate circulation of the control cord by an
operator of the
system. As will be appreciated, one control system component MA has its
circulating
control cord 78 at the left end of the headrail 46 while the other control
system 548
component has its control cord at the right end of the headrail.
[0070] The drive pulley 74 is operatively joumaled within a conventional
brake or
two-way clutch 82 so that when the control cord 78 associated with the drive
pulley is not
being circulated in one direction or another, the brake retains the drive
pulley in a fixed
position. Movement of the control cord in one direction or the other releases
the brake to
permit the desired rotation as long as the control cord is being circulated.
An example of
such a brake can be found in U.S. Patent No. 7,571,756, which is of common
ownership
with the present application,.
[00711 At the output end of the brake 82, a gear reduction unit 84
is provided to
reduce the output speed of rotation in relation to the input speed. In other
words, a full
rotation of the input to the gear reduction unit might generate one-third or
one-half of a
rotation at the output end. Such gear reduction units may or may not be
necessary
7
CA 2797850 2017-08-28
depending upon the weight of the shade material and the width of the covering
as
dictated by the length of the headrail 46. If the gear reduction unit is
utilized, it could be
of a conventional type which is well known in the art.
[0072] The output end of the gear reduction unit 84 receives the left
end of the
non-circular drive shaft 68 so as to rotate the drive shaft at a predetermined
rate of
rotation dependent upon the rate of rotation of the drive pulley 74. Rotation
of the drive
shaft rotates a conventional cord wrap spool 86C, which is mounted on the
shaft for
unitary rotation therewith and is rotatably seated within a cradle 88 fixed
within the
headrail 46 in a conventional manner. A typical wrap spool and cradle can be
found and
disclosed in detail in the aforenoted U.S. Patent No. 7,571,756, which is of
common
ownership with the present application. Suffice it to say that the cord wrap
spool anchors one
end of a lift cord 90C whose opposite end supports the bottom rail so that as
the bottom rail
is raised or lowered by rotation of the spool, the lift cord associated
therewith is wrapped
about or unwrapped from the spool. The spool is designed to automatically
shift axially as
the lift cord material is wrapped thereabout to prevent entanglement, but as
will be
appreciated, under some conditions if the spool is overwrapped or
underwrapped, the
associated lift cord can become entangled. It is the cord tension control
system of the
present invention that has been designed to reduce the possibility of such
entanglement.
[0073] To the right of the previously described wrap spool 86C and also
mounted
on the drive shaft 68 for unitary rotation therewith is a threaded shaft
element 92 of the
cord tension system 64 of the present invention, which will be described in
more detail
hereafter. Suffice it to say that the threaded shaft element has a
longitudinal passage 94
=
therethrough of the same non-circular cross-section as the drive shaft so that
the
threaded shaft rotates in unison with the drive shaft.
[0074] The drive shaft 68 supports a second cord wrap spool 86E on
the
opposite side of the cord tension system 64 from the cord wrap spool 86C
previously
described with the second cord wrap spool being identical to the first and
again rotatably
seated in a cradle 88 secured within the headrail 46. A lift cord 90E
associated with the
second wrap spool is connected to the bottom rail as the rift cord 90C
emanating from
the first cord wrap spool. For purposes of the present disclosure and as will
be
described in more detail hereafter, the lift cords 90C and 90E associated with
the wrap
spools 86C and 86E, respectively, previously described extend downwardly and
are
secured to the bottom rail 50 to effect raising and lowering of the bottom
rail depending
upon the direction of rotation of the drive shaft 68 and consequently the wrap
spools NC
and 86E operatively associated therewith. The right end of the drive shaft, as
shown in
8
CA 2797850 2017-08-28
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
FIG. 3A, is journa led in the end cap 72 at the right end of the headrail 46
in any
conventional manner so that the drive shaft is supported within the headrail
for
bidirectional rotation depending upon the direction of circulation of the
control cord 78
associated therewith.
[0075] With reference to FIG. 4, the lift cords 90C and 90E associated with
the
first and second cord wrap spools 86C and 86E, respectively, previously
described can
be seen extending downwardly from their associated wrap spools through a
grommet 96
in the top rail 48 and subsequently downwardly to the bottom rail 50 where
they extend
through a first grommet 98 and then back upwardly through a second grommet 100
where the end of the lift cord can be knotted or otherwise provided with an
attachment to
the bottom rail. In this manner, it will be seen that rotation of the
previously described
drive shaft 68 and the associated wrap spools 86C and 86E in one direction or
the other
will cause the bottom rail to raise or lower independently of the top rail.
[0076] The control system component 54B, which has not been
specifically
described but which is shown in FIG. 3A to the right of the previously
described control
system component 54A, has its cord wrap spools 86B and 86D supporting lift
cords 90B
and 90D, which extend downwardly from the first and second lift spools of the
second
control system component and are extended through a first grommet 102 in the
top rail
and subsequently upwardly through an adjacent grommet 104 where the end of the
cords 90B and 90D can be knotted or otherwise secured to the top rail 48 such
that
rotation of the second component of the control system, which is independent
of the first
component, will cause the top rail to raise or lower as the lift cords 90B and
90D are
wrapped or unwrapped from their associated spools 86B and 86D, respectively.
[0077] From the above, it will be appreciated that if an operator
wanted to raise
or lower the bottom rail 50 while leaving the top rail 48 unmoved, the first
component 54A of the control system would be operated by rotating its
associated
control cord 78. The top rail can be raised or lowered identically by
circulating its
associated control cord. In this manner, the shade material 52 can be
positioned in an
infinite number of conditions between the top and bottom rails with four of
those
conditions illustrated in FIGS. 5A-5D. In FIG. 5A, the shade is fully extended
across the
architectural opening 42 in which it is mounted by lowering the bottom rail to
the bottom
of the opening and raising the top rail adjacent to the headrail 46 of the
covering. In FIG.
5B, the bottom rail is left at the bottom of the architectural opening while
the top rail has
been lowered approximately half way across the opening. FIG. 5C illustrates
the top rail
having been left in the position shown in FIG. 5B but the bottom rail having
been raised
into adjacent relationship with the top rail. FIG. 5D shows the top rail
positioned at the
9
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
top of the opening, and the bottom rail moved into adjacent relationship
therewith so that
the covering is fully retracted in a raised position.
[0078] Looking now specifically at the cord tensioning system of the
present
invention, which is provided to prevent entanglement of the lift cords 90 upon
operation
of the control cords 78, it will be appreciated from the above description
that each control
system component 54A and 54B has a component of the cord tensioning system in
the
form of an identical threaded shaft 92 mounted on an associated drive shaft 68
for
unitary rotation therewith. Each threaded shaft is probably best seen in FIGS.
14 and 15
to include a threaded main body 106 with a reduced diameter small end 108 at
one end
of the threads and an enlarged end 110 at the opposite end of the threads. The
longitudinal passage 94 is shown through the entire length of the threaded
shaft of non-
circular cross-section which is correlated with the cross-section of the drive
shaft to
provide unitary rotation of the threaded shaft with the drive shaft on which
it is mounted.
The enlarged end of each threaded shaft has a large ring 112 integrally formed
thereon
at a short spacing from the associated end of the threaded shaft and at a
spaced
distance from the large ring toward the opposite small end of the threaded
shaft is an
integral middle or intermediate ring 114. Spaced from the intermediate ring,
again
toward the opposite small end of the threaded shaft, is an integral inner ring
116 of the
same diameter as the middle ring with the face of the inner ring closest to
the small end
of the threaded shaft having a radial tapered tooth or catch 118 formed
thereon for a
purpose to be described hereafter. As probably best seen in FIG. 3A, the
enlarged
end 110 of each threaded shaft is positioned on its associated drive shaft 68
so as to be
at the right end of the threaded shaft as viewed in FIG. 3A.
[0079] Each threaded shaft 92 has an identical abutment nut 120
threaded
thereon with the abutment nut having a threaded passage 122 therethrough for
threaded
receipt on the threaded shaft, and enlarged upper 124 and lower 126 ends. A
longitudinal groove 128 is provided in the lower surface of the lower end for
a purpose to
be described hereafter, and a catch block 130 is affixed to the face of the
abutment nut
facing the enlarged end 110 above the threaded passage 122 so as to confront
the
opposing face of the inner ring 116 having the catch 118 formed thereon. In
this
manner, the catch can abut the block when the abutment nut is positioned
adjacent to
the inner ring to positively prevent further rotation of the threaded shaft in
one direction.
[0080] With reference to FIGS. 3A, 6, and 7, each threaded shaft 92
can be seen
to be rotatably positioned within an open topped housing 132 which is
connected in any
suitable manner to the headrail 46 so as to be non-movable relative thereto.
The open
topped housing rotatably supports each threaded shaft at opposite ends thereof
with
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
cradles 134 formed interiorly of the housing at opposite ends thereof. The
threaded
shafts are displaced longitudinally of each other a small distance as possibly
best
appreciated by reference to FIG. 6. Looking first at the uppermost shaft 92A
as viewed
in FIG. 6 or the shaft to the left, as viewed in FIG. 3A, a space or
circumferential
groove 136 defined between the large ring 112 and the middle ring 114 of the
threaded
shaft receives a guide finger 138 formed in the housing to prevent the
threaded shaft
from shifting significantly longitudinally to the left as viewed in FIG. 6. A
similar
finger 140 is formed on the wall of the housing to protrude into a
circumferential
space 142 defined between the middle ring and the inner ring 116 to assist in
preventing
longitudinal translation of the threaded shaft particularly as it is rotated.
With reference
to the lower threaded shaft 92B, as seen in FIG. 6, or the threaded shaft to
the right, as
viewed in FIG. 3A, it will be seen that its large ring 112 is guided within a
groove 144
provided in the inner surface of the housing, and another finger 146 is formed
in the
adjacent wall of the housing that protrudes into the annular space 142 between
the
middle ring 114 and the inner ring 116 to prevent the associated threaded
shaft from
shifting longitudinally or axially particularly during rotation of the
threaded shaft. It can
also be appreciated in FIG. 6 that the large ring of the lower threaded shaft
protrudes
into the gap 142 between the middle ring and the inner ring of the upper
threaded shaft
which further assures a positive axial relationship between the two threaded
shafts so
that they are always positively positioned axially relative to each other at
the
predetermined position desired which is illustrated in FIG. 6.
[0081] With reference to FIG. 9, each abutment nut 120 can be seen
threadedly
mounted on its associated threaded shaft 92 and slidably guided within the
housing 132
by a longitudinal rib 148 extending inwardly along the bottom surface of the
housing.
The abutment nuts are therefor prevented from rotating upon rotation of their
associated
threaded shaft. Rather, the nuts are translated along the length of the
threaded shafts
depending upon the direction of rotation of the shafts. It should also be
appreciated by
reference to FIG. 9 that the abutment nuts laterally overlap each other so
that they are
incapable of passing by each other along the length of their associated
threaded shafts.
In this manner, when an abutment nut engages the other abutment nut, the
threaded
shafts are positively prevented from further rotation in a direction causing
the abutment.
Similarly, each abutment nut is positively prevented from further rotation
toward the
enlarged end 110 of the threaded shaft once the block 130 on the face of the
abutment
nut engages the catch or tooth 118 on the face of the inner ring 116. The
operative
engagement between the tooth and the block provide a positive means for
immediately
preventing further rotation of the threaded shaft even if the materials from
which the nut
11
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
and the shaft are made might be soft enough to allow some compression of the
nut into
the inner ring which would thus permit a slight degree of rotation beyond that
desired.
[0082] It will be appreciated that the tension control device 64 of
the invention is
designed to maintain a very precise and positive control of rotation of the
threaded
shafts 92 and drive shafts 68 and therefore also the raising and lowering of
the lift cords
and their associated rails. This improves the control over the lift cords as
they are
wrapped around or unwrapped from their associated wrap spools, and without
such
positive control, entanglement of the lift cords has presented a problem in
prior art
systems. The entanglement normally occurs when one movable rail is moved
toward the
other and continues the movement thereby driving the second movable rail out
of its
position creating slack in the lift cords associated with the second rail
which will
sometimes create entanglement where the associated lift cords are wrapped
around
their associated cord wrap spools.
[0083] Due to the overlapping of the abutment nuts 120, it will be
appreciated the
control system components are operatively interrelated and by desirably and
appropriately positioning the abutment nuts during assembly of the covering
the desired
control over the lift cords to prevent entanglement can be obtained as one
rail can be
prevented from engaging and driving the other rail out of position.
[0084] In order to best describe the operation of the system, FIGS.
5A-5D are
correlated with FIGS. 16A-16D, respectively, to show the position of the
abutment
nuts 120 at the relative and corresponding positions of the top 48 and bottom
50 rails as
illustrated in FIGS. 5A and 5D. Obviously, there are an infinite number of
relative
positions of the top and bottom rails, but for purposes of understanding the
present
invention, only four of those positions and thus conditions of the
architectural covering 40
are illustrated.
[0085] As mentioned previously, the top threaded shaft 92A, as viewed
in
FIGS. 16A-16D, is associated with the bottom rail 50 so that rotation thereof
causes the
bottom rail to raise or lower. The bottom threaded shaft 92B, as viewed in
FIGS. 16A
and 16D, is associated with the top rail 48, and its rotation is correlated
with the
movement of the top rail. Looking first at FIGS. 5A and 16A, it will be
appreciated the
top rail is positioned at its extreme highest position adjacent to the
headrail 46, and the
position of the associated abutment nut is close to the left end of the
associated
threaded shaft 92B or the lower shaft, as viewed in FIG. 16A. The bottom rail
is
positioned at its extreme lowest position adjacent the bottom of the
architectural opening,
and its associated abutment nut is positioned at the right end of its
associated threaded
shaft 92A, or the upper threaded shaft, as viewed in FIG. 16A. Accordingly,
the lower
12
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
abutment nut can never be positioned further left than it appears in FIG. 16A
as the top
rail is as high as it can go and the abutment nut associated with the bottom
rail is as far
right as it can go inasmuch as the bottom rail is as low as it can possibly
be.
[0086] Looking next at FIGS. 5B and 16B, it will be appreciated the
bottom rail 50
is still at its extreme lowest position so that the abutment nut 120
associated therewith
(the upper nut as viewed in FIG. 16B) has not moved and is at the right end of
its
threaded shaft 92A or the upper threaded shaft as viewed in FIG. 16B. The
upper
rail 48, however, has been lowered and as it is lowered its associated
abutment nut (the
nut on the lower threaded shaft as viewed in FIG. 16B) has been translated to
the right.
[0087] Looking next at FIGS. 5C and 16C, the upper rail 48 remains at the
location it was in FIG. 5B and, accordingly, its corresponding abutment nut
120 on the
lower threaded shaft 92B, as viewed in FIG. 16C, is at the same position it
occupied in
FIG. 16B. The bottom rail 50, however, has been raised and as it is raised,
its
associated abutment nut on the top shaft 92A, as viewed in FIG. 16C, has been
translated to the left and in fact has abutted the lower abutment nut so that
no further
rotation in that direction is possible. This, of course, gives a very positive
stoppage of
rotation of either threaded shaft which would cause their associated abutment
nuts to
move further toward each other and thus the associated cord wrap spools are
also
positively stopped from rotation which prevents further movement of either
rail and
possible entanglement of the lift cords associated therewith. By properly
positioning the
abutment nuts on their associated threaded shafts, the spacing between the
upper and
lower rails can be controlled regardless of where they are positioned within
the
architectural opening itself, and they can never be closer than the
predetermined
spacing, for example, illustrated in FIG. 5C and 5D.
[0088] With reference to FIGS. 5D and 16D, it will be appreciated the upper
rail 48 has been raised to the top of the opening 42 so that its associated
abutment
nut 120 (on the lower shaft 92B as viewed in FIG. 16D) has been translated to
the
position it occupied in FIG. 16A, and at the same time, the bottom rail 50
associated with
the upper abutment nut 120, as viewed in FIG. 160, has been raised to the
desired
closest spacing of the bottom rail to the top rail, which of course occurs, as
mentioned
previously, when the abutment nuts engage each other. The abutment of the
abutment
nuts, as mentioned previously, provides a very positive and abrupt system for
preventing
further rotation of the associated drive shafts so that further compression of
the fabric
between the upper and lower rails and worse yet undesirable movement of a rail
out of
position and therefore possible entanglement of the lift cords is avoided.
13
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
[0089] It will be appreciated from the above that a system has been
employed for
not only raising and lowering upper and lower rails of a top down/bottom up
covering
between infinitely variable positions, but also through use of the cord
tensioning system
described provides a very positive and immediate system for preventing
undesired
movement of the rails which can cause entanglements and thus malfunctioning of
the
covering.
[0090] Referring next to FIGS. 17A-30E, a second arrangement 150 of a
top
down/bottom up covering with a second embodiment 152 of a cord tension control
system is illustrated. It will be appreciated from the description that
follows, however,
that a control system 154 including components 154A and 154B, but for the cord
tension
control portion 152 thereof, is identical to that previously described in that
only two rails
are movable within the covering even though the movable rails are associated
with two
distinct compressible panels 156 and 158 of shade material.
[0091] Looking at FIGS. 17A-18, this arrangement 150 of the top
down/bottom up
covering can be seen to include a headrail 46 identical to that described in
connection
with the first arrangement, a top panel 156 of collapsible shade material, and
a bottom
panel 158 of collapsible shade material. The top panel 156 of shade material
has its
uppermost cell suspended from the headrail 46 in a conventional manner, such
as with
an anchor strip (not shown), and its bottom edge connected to a top rail 160
through use
of an anchor strip through the lowermost cell of the top panel. The uppermost
cell of the
bottom panel 158 is connected to the lower surface of a middle rail 162, again
with an
anchor strip (not shown) or through any other suitable system, with the bottom
or
lowermost cell of the bottom panel being connected to a bottom rail 164 in a
similar
manner. The bottom rail of this arrangement of the covering is secured to the
threshold 166 (FIGS. 21A-21E) of the framework of the architectural opening 42
so it
never moves. Similarly, the headrail is mounted on suitable brackets (not
shown) so it
never moves. The top rail 160 and middle rail 162, however, are movable up and
down
relative to and independently of each other through a control system 154A or
154B of the
type described in connection with the first arrangement of FIGS. 1-16D with
the
exception that the cord tension system 152 is a second embodiment thereof.
[0092] Referring to FIG. 17A, the covering 152 is fully extended with
the top
panel 156 fully extended and the bottom panel 158 fully extended in which
position the
top rail 160 is contiguous with the middle rail 162. FIG. 18 illustrates the
top rail having
been raised to retract the upper panel into a collapsed position adjacent the
headrail 46,
and the middle rail has been lowered to collapse the lower panel in a
retracted position
14
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
adjacent to the bottom rail 164. FIG. 17B is an enlarged drawing showing the
covering in
the position of FIG. 17A with portions removed due to size limitations.
[0093] Looking next at FIGS. 19A-20, it will be appreciated, as
mentioned above,
that a headrail 46 with two identical but reversed control system components
154A and
154B are utilized for operating the covering. The only difference in the
control system
components of this arrangement and the arrangement of FIGS. 1-16D resides in a
different cord tensioning system 152, which will be described hereafter, and
the fact that
static, fixed guide cords 168 (FIGS. 19A, 19B and 20) extend from an anchored
location
in the headrail 46 to the bottom rail 164 to guide movement of the top 160 and
middle 162 rails in operation of the covering. In this arrangement of the
covering, the
control system component 154A shown in FIG. 19A to the left and above the
other
component 154B has lift cords 170C and 170F associated with its wrap spools
172C and
172F, respectively, with cords 170C and 170F extending downwardly and having
their
lower ends anchored to the middle rail 162 (FIG. 20) in a manner similar to
that
described in the first arrangement of the invention.
[0094] The lift cords 170B and 170E associated with the other or lower
control
system component 154B, as illustrated in FIG. 19A, extend downwardly and are
anchored to the top rail, again in the same manner as described with the first
arrangement of the invention. Accordingly, operation of the upper or left
control system
component 154A, as viewed in FIG. 19A, raises or lowers the middle rail 162
while
operation of the lower or right component 154B, as viewed in FIG. 19A, raises
or lowers
the top rail 160. As can be appreciated, the top rail and the middle rail are
each moved
vertically independently of each other and, therefore, can be positioned at
any desired
location within the architectural opening within the operating parameters of
the cord
tensioning system 152. With this arrangement of a covering, however, the upper
panel
segment will always extend from the headrail to the top rail regardless of the
positioning
of the top rail, and the lower shade component will always extend from the
bottom rail to
the middle rail regardless of the positioning of the middle rail.
[0095] Referring next to FIGS. 22-29, the cord tension control system
152 will be
described. The cord tension control system of this embodiment of the invention
again
includes two identical threaded shafts 174 and two identical abutment nuts
120, which
are identical to those previously described and shown in FIGS. 13 and 14. The
threaded
shafts, as seen best in FIGS. 28 and 29, have a threaded elongated body
portion 178, a
small diameter end 180 and a large diameter end 182 with a longitudinally
extending
passage 184 therethrough of non-circular cross-section to correlate with that
of the drive
shaft for the control system component with which it is associated so that the
threaded
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
shaft rotates in unison with an associated drive shaft 68. The large diameter
end of the
threaded shaft has an outer ring 186 formed thereon of a first diameter that
is spaced
from a middle ring 188 of the same diameter to define a circumferential
channel 190
therebetween. The middle ring in turn is spaced from a large diameter ring 192
forming
still another circumferential channel 194 therebetween with the large diameter
ring
having a tapered radial catch or tooth 196 formed thereon facing the smaller
end 180 of
the threaded shaft. The first and middle rings each have an alignment tab 198
formed
thereon which has no operative function other than to facilitate assembly of
the threaded
shaft on the drive shaft at a desired relationship between the drive shaft and
the
threaded shaft.
[0096] The cord tension control system 152, as mentioned, further
includes an
abutment nut 120 on each threaded shaft with the abutment nuts, as mentioned
previously, being identical to those described in connection with the first
embodiment of
the cord tension control system. The threaded shafts are rotatably supported
within an
open topped housing 200 shown best in FIG. 27 and shown in FIGS. 24-26 in
operative
relationship with threaded shafts 174A and 1746. As seen in FIG. 22, however,
it will be
appreciated the threaded shafts are offset longitudinally of each other
similar to the first
described embodiment and have the opposite ends of the threaded shafts
rotatably
received in cradles 202 that positively position the threaded shafts relative
to the
housing. The housing, of course, is fixedly positioned within the headrail 46
in any
suitable manner.
[0097] Referring first to the upper threaded shaft 174A, as viewed in
FIG. 22 as
well as referencing FIGS. 24-27, it will be appreciated the housing 200 has an
upstanding finger 204 formed on the bottom wall, which is adapted to extend
into the gap
between the outer 186 and middle 188 rings on the threaded shaft to prevent
the upper
threaded shaft from shifting to the left. A stanchion 206 is formed on the
side wall of the
housing immediately adjacent to the middle ring of the upper threaded shaft
with the
stanchion having a biasing spring 208 mounted thereon with one arm 210 of the
spring
extending through and being anchored in a hole 212 in the side wall of the
housing and
the opposite end of the spring engaging the surface of the large ring 192
which faces the
middle ring. The spring 208 therefore biases the threaded shaft to the left,
as viewed in
FIG. 22, holding the outer ring against the abutment finger 204 to assure the
desired
positioning of the shaft relative to the housing and thus to the headrail
itself.
[0098] Looking at the lower threaded shaft 17413, as viewed in FIG.
22 as well as
to FIGS. 24-27, it will be seen that another abutment finger 214 is provided
in the bottom
wall of the housing and positioned in abutment with the face of the large ring
192 that
16
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
faces the middle ring 188. This abutment finger prevents the lower threaded
shaft from
shifting to the right. The lower threaded shaft is biased to the right with a
second
spring 216 mounted on a second stanchion 218 on the opposite side wall of the
housing
with the spring being identical to the first spring having one finger
extending through and
being anchored in a hole 220 in the side wall and the opposite arm 222 of the
spring
engaging the face of the outer ring 186 that faces the middle ring so as to
bias the lower
threaded shaft to the right and into positive abutment with the abutment
finger 214. The
spring biasing system has been found desirable for positively positioning the
threaded
shafts relative to the housing so that there is no movement even during
rotation of the
threaded shafts and resulting translation of the abutment nuts mounted
thereon.
[0099] Looking next at FIGS. 21A-21E showing five different positions
of the
covering and their correlated views of the cord tension control system 152
shown in
FIGS. 30A-30E, respectively, it can be appreciated how the cord tension
control system
provides a positive system for controlling rotation of the drive shaft 68 and
thus the wrap
spools 172 to prevent entanglement of the lift cords 170 associated with the
wrap spools.
[00100] Looking first at FIG. 21A, it will be seen the top rail 160 is
positioned
approximate to the middle of the architectural opening 42 with the middle rail
162
positioned contiguous therewith also at the approximate center of the
architectural
opening. As seen in FIG. 30A, the abutment nut 176 on the upper shaft 174A is
at the
approximate longitudinal center of the associated threaded shaft and in
abutment with
the abutment nut on the lower threaded shaft 174B, which is also at the
approximate
longitudinal center of its threaded shaft. It is when the rails 160 and 162
are in abutment,
as shown in FIG. 21A, that it is desired that the abutment nuts also be
abutted to prevent
an operator from trying to move either the upper or middle rail toward the
opposite of the
upper or middle rail more than is desired which may cause entanglement of the
lift cords
associated with the wrap spools. Accordingly, the abutment of the nuts, as
seen in FIG.
30A, positively prevents the rails from moving beyond their abutment, as shown
in FIG.
21A.
[00101] In FIG. 21B, the upper rail 160 has been raised a short
distance while the
middle rail 162 has been lowered a shortened distance which causes the upper
abutment nut 176 to shift to the right, and the lower abutment nut to shift to
the left into
separate positions.
[00102] Referring to FIG. 21C, the top rail 160 has been raised near
the
headrail 46 of the covering so that its associated nut 176 (the lower abutment
nut shown
in FIG. 30C) is closer to the left end of the threaded shaft 174B, and the
middle rail 162
has been raised into abutment with the top rail so that again the abutment
nuts are
17
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
engaged as no further movement of the rails toward each other is desirable as
it might
cause entanglement of the lift cords. Of course the abutment of the abutment
nuts
positively prevents any further movement and thus prevents entanglement.
[00103] Looking at FIG. 21D, the middle rail 162 has been lowered
fairly closely to
the bottom rail 164, and the top rail 160 has been lowered into abutting
contiguous
relationship with the middle rail. Again, while the nuts 176 on their
associated shafts
have been shifted to the right, since both the top rail and the middle rail
have been
lowered, they are abutting as are the top and middle rails to positively
prevent any further
movement of the rails toward each other. As mentioned above, this prevents the
possibility of entanglement of the lift cords.
[00104] Referring to FIG. 21E, the top rail 160 has been raised
adjacent to the
headrail 46, and the middle rail 162 has been lowered adjacent to the bottom
rail 164 so
that the nuts 176 associated with the rails, as seen in FIG. 30E, are
separated as
dictated by the positioning of the top and middle rails.
[00105] Accordingly, it will be appreciated with this embodiment of the
cord
tension control system 152 that the possibility of entanglement of the lift
cords
associated with the wrap spools on the drive shafts 68 is diminished by
preventing the
top and middle rails from being moved further toward each other than is
desirable as
such compressive movement of one rail toward the other has been known to cause
entanglement of the lift cords particularly when one moving rail moves a
second movable
rail out of position creating slack in the lift cords associated with the
second movable rail.
Further in this embodiment, the threaded shafts are positively positioned so
as not to be
effected by their rotation or the abutment of the abutment nuts by the spring
biasing
systems which hold the threaded shaft against a fixed finger formed in the
housing.
[00106] A third embodiment of a cord tension control system pursuant to the
present invention is shown in FIGS. 31-40 with this embodiment of the cord
tension
control system being applicable for use in connection with either one of the
top
down/bottom up covering arrangements previously described. In other words, the
third
embodiment of the cord tension control system would work with an arrangement
where
there was a single collapsible panel between a movable top and bottom rail or
in an
arrangement where there were two collapsible panels with an upper collapsible
panel
extending from a fixed headrail to a movable top rail, and a bottom panel
extending from
a movable middle rail to a fixed bottom rail. As in the first two described
embodiments of
the cord tension control system, the third embodiment includes an open-topped
housing 240 to be described in detail hereafter with two identical threaded
shafts 242
being rotatably positioned therein and keyed to associated drive shafts 244
for one of the
18
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
movable rails in the covering and with each threaded shaft having a threaded
abutment
or adjustment nut 246 thereon which overlaps the nut of the adjacent threaded
shaft so
that the nuts abut each other when no further movement of one of the movable
rails in
the covering is desired.
[00107] Referring first to FIGS. 32 and 33, the threaded shaft 242 used in
the third
embodiment is illustrated and can be seen to have a threaded segment 248 along
a
hollow shaft 250 with the hollow shaft having a passageway 252 therethrough of
noncircular cross-section to correlate with that of the drive shaft 244 so
that the threaded
shaft rotates in unison with the drive shaft as in the first two described
embodiments. At
a large end of the threaded shaft, an outer ring 254 and an inner ring 256 are
provided of
equal diameter and which are spaced so as to define a circumferential groove
258
therebetween. The outer ring has a radial tooth 260 extending away from the
inner ring
on its outer face with the tooth defining a flat engagement surface 262
extending in an
axial direction while the inner ring has an identical abutment tooth 264 on
its inwardly
directed face which faces away from the outer ring. The threaded shafts are
adapted to
be seated in the open-topped housing 240 of FIG. 31 as seen probably best in
FIGS. 34,
36 and 37 so that they extend in opposite directions, that is with the large
end of one
shaft (the upper shaft as viewed in FIGS. 34, 36 and 37) being at the right
end of the
housing and the large end of the lower threaded shaft as viewed in FIGS. 34,
36 and 37
being at the left end of the housing. The housing has appropriate cradles 266
and 268 at
opposite ends to rotatably support the associated ends of the threaded shafts
so that the
threaded shafts can rotate within the cradle and as they rotate the associated
abutment
nuts 246 are translated along the length of the threaded shafts as in the
prior described
embodiments. Rails 270 on the bottom wall 272 of the housing prevent the nuts
from
rotating relative to the housing but permit the nuts to translate along the
lengths of the
threaded shafts as the associated threaded shafts are rotated by the
associated drive
shafts.
[00108] As best appreciated by reference to FIG. 31, the end of the
housing 240
having the cradle 266 supporting the large end of a threaded shaft 242 has a
transversely extending rib 274 of rectangular cross-section projecting
upwardly from the
bottom wall 272 of the housing and spaced outwardly or toward the adjacent end
of the
housing a vertically extending abutment tab 276 is positioned to abut the
radial tooth 260
on the outer ring 254 as will be described hereafter. Inwardly of the
transverse rib 274 is
a generally Z-shaped spring arm 278 which could be metal or plastic having a
lower
horizontal leg 280 anchored to the housing as seen, for example, in FIGS. 38
and 39, an
intermediate leg 282 extending vertically in a neutral position and an upper
leg 284
extending toward the opposite end of the housing from that of the lower leg.
The free
19
CA 02797850 2012-10-29
WO 2012/150946 PCT/US2011/036122
edge 286 of the upper leg is positioned to engage the inner ring 256 of the
associated
threaded shaft and yieldingly resists movement of the shaft in a direction
toward the end
of the housing supporting the large end of the threaded shaft.
[00109] Referring to FIG. 36, the abutment nuts 246 are shown abutting
each
other which would be the case when the movable rails associated with each
threaded
shaft 242 are closely positioned relative to each other and at a position
where it is not
desired that they move any further toward each other. FIG. 34 shows the
abutment nuts
separated as when the associated movable rails are separated from each other,
and
FIG. 37 shows the abutment nuts even further separated and with the abutment
nut of
the bottom threaded shaft as viewed in FIG. 37, which is associated with the
uppermost
one of the two movable rails, in abutment with the inner ring 256 of its
associated
threaded shaft and with a radial rib 288 on the abutment nut engaged with the
radial
tooth 264 of the inner ring to prevent any further rotation of the threaded
shaft in a
direction which would cause its abutment nut to move toward the inner ring.
[00110] Referring to FIGS. 38 and 39, the operation of the spring arm 278
and the
transverse rib 274 and abutment tab 276 are illustrated. In other words, FIGS.
38 and 39
are sections through the upper threaded shaft 242 as viewed in FIGS. 34, 36
and 37,
which threaded shaft is associated with the lowermost one of the two movable
rails in the
covering. If the control cord for the lower movable rail is being rotated in a
direction
causing the abutment nut 246 on the upper threaded shaft to translate to the
left as
viewed in FIGS. 38 and 39, or if the lower threaded shaft associated with the
uppermost
movable rail in the covering is rotated so that its abutment nut is translated
to the right,
as shown in FIG. 39, the nuts will ultimately become engaged as illustrated in
FIG. 39.
When this happens, as shown in FIG. 39, the abutment nuts will react by
initially pushing
their associated threaded shafts in opposite directions toward their large
ends against
the bias of the associated spring arms 278 which allow the threaded shafts to
shift a
small amount in a direction toward their large end until the outer ring on the
threaded
shaft engages or substantially engages an associated abutment tab 276 in the
housing,
which is then aligned with the radial engagement tooth 260 on the outer ring,
as seen in
FIG. 39. This, of course, positions the threaded shafts so they cannot be
rotated in a
direction which would cause their associated abutment nuts to translate toward
each
other thus terminating movement of their associated rails in the covering.
[00111] It will therefore be appreciated that the cord tension control
system of the
third embodiment allows an initial yielding movement of the movable rails
toward each
other, but once the initial yielding movement has occurred, there will be a
very positive
blockage of movement of one rail toward the other due to the interrelationship
of the
CA 02797850 2012-10-29
WO 2012/150946
PCT/US2011/036122
radial teeth 260 on the associated abutment tabs 276 within the cord tension
control
system.
[00112] Pursuant to the above, it will be appreciated that a top
down/bottom up
covering has been shown in two different arrangements and with three different
embodiments of a cord tension control system that resists lift cords from
entangling on
their wrap spools. The entanglement is prevented by correlating abutment nuts
on
threaded shafts with the wrap spools and the associated lift cords to prevent
over-
movement of rails toward each other, which over-movement has been found to
increase
the likelihood of entanglement of the lift cords.
[00113] Although the present invention has been described with a certain
degree
of particularity, it is understood the disclosure has been made by way of
example, and
changes in detail or structure may be made without departing from the spirit
of the
invention as defined in the appended claims.
21
