Note: Descriptions are shown in the official language in which they were submitted.
9~
Background and Su~mary of the Invention
This invention relates to collapsible and expand-
able tubular structures, and more particularly to a
curtain comprised of flexible strips made in-to tubular
units by bands of adhering contact. The tubular structure
can be used as an insulating curtain over openings such
as doors, windows and the like. The invention also
relates to the method of produciny such cur-tains from
continuous strips of thin~film material.
Flexible insulating curtains having tubu~r units, I
along with methods of making such structures, are known
in the pr~or art. One such cur-tain is found in U. S.
Patent No, 4,019,554 and a method for making that curtain
is found in U. S. Patent No. 3,963,~49. However, such
prior art curtains require relatively narrow tubular foils ;
of 2 to 3 inches in diameter and use a single band of
adhesive between adjacent foils. ~s winding speed is
limited by the rate at which adhesive can be applied to
~; the foil, the prior art method is qui-te slow. Furthermore,
the curtain produced has only one tubular thickness.
~ beehive like wall structure with mul-tiple
cells for insulating purposes is illustrated in Finnish
Patent No. 23939 dated May 31, 1950. The structure is
made by ~luing thin plates o paper to each other and to
outside surface boards at areas of contact on alternating
sides o~ the plates. ~lthough the cellulated structure
can be pressed together for transporting and expanded for
installation, the insulation board has relatively few cells
in each row and those cells could be compressed and
- 1-- ,~,"~
9~
expanded only a few times wi-thou-t deterioration of the
wall material. According to this patent, th.e area of
ylued contact between adjacent plates must be limited to
a maximum of 1/3 of the width of the air cell, presumably
to minimize the severe distortion that would occur in the
; walls of the partial cells adjacent to each surface board.
Since tne width of the glued area is transverse to the
direction in which insulation is desired, the air cells
must be fully expanded for effective insulati..on.
Such disadvantages and limitations of the prior
art are overcome by the tubular structure o~ the present
invention which may have a plurality of insulating cavities
both in the direction of curtain height and in the
direction of curtain thickness. While the insulating
properties of one tubular unit are significant, much
better insulation can be provided by a plurality of
tubular units across the curtain thickness. The
in:sulating characteristics of those unlts are further
: enhanced by aligning the bands of adhering contact in
~; 20 the direction to be insulated. The insulating effectiveness
of the tubular cavities is -thereby maximized and does not
change significantly with the degree of expansion.
The novel method disclosed for producing insulating
curtains is much simpler and faster and more economical
than heretofore known. A plurality of curtains are
or /~e/5
simultaneously produced from strips~of relatively
~,_, ~ .
inexpensive material. The individual strips may be of
any thin flexible material, and are preferably of thin film
plastic. Although narrow relative to length, the strips
may be many feet in width, the width being limited only by
practical considerations o-E winding sheet material.
In practicing the method, two or more s-trips are
pulled simultaneously from multiple sources and each
passed through a station at whlch adhesive is applied
to one surface in multiple transversely spaced bands. The
bands are applied in a staggered relationship and the
strips arranged adjacent to each other with an adhesive
surface opposing a non-adhesive surface. The bands are
preferably of a substantially uniform width and spaced
transversely from each other at substantially the same
distance. The width of each band corresponds to the
desired width of the corresponding tubular unit in its
expanded state. Accordingly, the sum of the width
dimensions of all bands spaced transversely across two
adjacent strips will equal approximately the overall
thickness of the curtain when fully expanded.
After application of the adhesive bands, the strips
are interleaved and wound in superimposed layers about
the periphery of a forming member so as to interlaminate
adjacent strips and the bands of adhesive therebetween.
The staggered bands between successive s-trips produce
tubular units formed with a lower wall from one layer and
an upper wall from the next superimposed layer. The
upper and lower walls are adheringly secured together bv
bands of contact on opposite sides of -the tubular cavity
and each tube thus formed is adheringly secured to the
next superimposed tube by a band of contact across a
midsection of the upper tube wall. The side bands and
~ ~69~
the mid band all extend longitudinally along each tube
and define non-adheriny sidewalls therebetween. Tubular
units so arranged will expand or open when stxetched
in a direction transverse to the plane of the strips.
~ s used in -this specification, a row refers to
tubular units aligned with curtain height and not to
successive units in the direction of curtain thickness.
For a single row of tubes, the minimum number of trans-
verse bands is 3, additional bands being spaced transversely
depending upon the number of adjoining tube rows desired.
The number of layers wound upon the forming member is
chosen to yield the desired number of tubes in each row,
which in turn determines curtain helght. The inter-
lamination of only two strips is also possible and will
produce tubular units adjoined by bands of contact-across
the width of the strips. Thus, the curtain may have
successiVe tubular unlts adjoining in the direction of
curtaln height or in the direction of curtain thickness
or in both directions, the latter being pleferred.
After winding is complete, the resulting stack of
superimposed tubes is cut transversely r removed from the
forming member, and straightened into a linear stack.
Where the length of the tubes is a multiple o~ the desired
curtain width, a corresponding number of transverse cuts
are made to produce multiple curtains. Where there are
3 or more adjoining rows of tubes, a plurality o~ curtains
can also be produced hy one or more longitudinal cuts
down the tube length.
After straighteniny, the strips at the top and
~16~9~
bottom of the stack may be pulled apar-t to expand the tubes.
The curtain is extended to its full height when the tubes
are fully expanded. The end strips may then be moved
together to collapse one or more tubes. The tubes collapse
in accordion fashion along fold lines formed by the side
bands of contact. When flattened, the height of the tube
stack approximates the to-tal thickness of the superimposed
layers of film materialA To facilita-te manipulation of
the curtain, one end may be secured to a mounting slat ~nd
the other to a second sla-t movable relative to the first.
Pull cords and other conventional hardware may be added
to the slats to mount the curtain and selectively collapse
and expand -the tubular units in a manner similar to
venetian blinds.
The invention has many additional objects, some
of which are set forth here. The tubular structure can
be readily mounted, with or without supporting slats
, ~
along the end strips, in a number of different positions
for a wide variety of uses~ It has wide utility as a
thermal insulatin~ curtain and when extended vertically
can serve as a substitute Eor storm windows, storm doors
and the like The curtain can be extended horizontally
and pulled taut to serve as insulation beneath a floor or
above a ceiling. The individual tubes can be collapsed
and expanded numerous times and provide a curtain having
a long usable life. In its collapsed state, either as
mounted or as removed for storage, the curtain folds into
a stack of thin flat strips neatly aligned in a column.
.~, ,
--5--
I ~$9~
Curtains of varying height can be made depending
upon the number of strips superimposed upon the forming
member. Multiple curtains of less height than originally
formed can also be made by cutting the linear stack of
tubes longitudinally in a direction transverse to curtain
height.
The composition of the strip material may be
selected to yield light admitting tubes (transparent or
translucent), light absorbing tubes (black or other dark
colors), or light reflecting tubes. A pigment material
may also be added to the adhesive used so that -the bands
of contact have slmilar llght controlling characteristics.
With light controlling bands, the degree of light admitted,
absorbed or reflected can be controlled by tilting the
upper and lower most strips by means of attached slats
which will in turn produce a corresponding tilt of -the
longitudinally extending bands in a manner similar to
the louvers or slats of a venetian blind. Similar ligh-t
controlling characteristics can be obtained by applying
appropriate coatings to one or more sections of each tube
wall
he tubular s-tructure has many other applications,
such as structural members for greenhouses and other
buildings requiring the admission of large amounts of light
and for modu]ar structures utilizing flexible sheet
material. The tubular units may be reinforced internally
; and positioned on end as self-supporting walls, folding
doors and other structural componen-ts. The tubes may
also be sealed and pressurized internally with air as
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. _ . ., . ... _ .. _ _ .. . . _ . . . ... _ _ ~ . . . .. _ _ .. . . ...
;~16~5~
s-tructural members for air supported domes and the like.
Numerous other objects and advantages of the
lnvention will be apparent to those skilled in -the ar-t
from this specifica-tion and the at-tached drawings.
Brief Description of the DraWings
The invention, both as to its structure and method
of manufacture, may be fur-ther understood by reference
to the detailed description below taken in conjunc-tion
with the accompanying drawings in which:
Figure 1 is a fragmentary perspective view of
the cur-tain of the inven-tion having a single row of
superimposed tubes.
Figure 2 is a perspective view of a modification
of the invention wherein the curtain has a plurality of
tube rows in the direc-tion of curtain thickness.
Figure 3 is a perspective view of the curtain of
Figure 2 showing a portion collapsed in-to a stack of
superlmposed -tubes and illustr~ting means for mounting
and selec-tively collapsing and expandin~ -the curtain.
,
Figure 4 is a perspective view of an apparatus for
making the tubular cur-tain according -to -the metho~ of the
invention. :
Figure 5 is an end view of -the tubular curtain
as removed from the apparatus of Figure 4 and s-traightened
into a linear s-tack of fully collapsed tubular units,
Figure 6 is an end view o the tubular curtain
of Figure 1 as cut from the stack of Figure 5 along cut
line yl and partially expanded.
Figure 7 is an end view showing the curtain of
--7--
g5~
Figure 6 in its fully expanded state.
Figure 8 is an end view of the tubular cur-tain of
Figure 2 as cut from -the stack of Figure 5 along cut line
Y and partially expanded.
Figure 9 is an end view showiny -the curtain of
Figure 8 in its fully expanded state.
Detailed Description of the Invention
One embodiment of the tubular curtain oE the
; present invention, generally designated 10, is shown in
Figure 1 of the drawings. The curtain is comprised of a
row of tubes Cl which are superimposed one atop the other
in the direction of curtain height as best illustrated
; in Figures 1 and 7. Each tube has the same structure as
tube 12 which will be described in detail. The tube 12
has an upper wall 14 and a lower wa]l 15, each wall having
two longitudinally extending edges. The edges o one wall
abut the corresponding edges of the other wall along bands
of contact 16 and 17 on opposite sides of the tubular
cavity. The portions of each wall within the bands of
contact 16 and 17 are adheringly secured-together hy
appropriate means compatible with the wall materlal,
preferably an adhesive. With reference to Figure 7,
upper wall 14 has two side sections 14a and 14c and a
mid section 14b, and lower wall 15 has two side sec-tions
, ]5a and 15c and a mid section 15b. Tube 12 is superimposed
atop an underlying tube 18 and adheringly secured thereto
along a band of contac-t coextensive with lower mid section
15b. An overlying tube 19 is superimposed atop tube 12
and adheringly secured thereto along a band of contact
5 ~
coextensive with upper mid section 14b.
Although curtain Cl can be hung directly by
attachment of uppermost strip 21 to an overhead structure,
it i5 preferably provided with a mounting slat 23 and a
movable slat 2~ of a much more rigid material, such as
wood or metal. The slats may be adjusted relative to
each other for collapsing and expanding the curtain by
means of a drawstring or pull cord 25 which passes through
a series of apertures 26 in the slats and intervening
tubes of the curtain. The end of cord 25 is knotted or
.
o-therwise secured at 27 to slat 24 so that the latter can
be selectively adjusted by manipulation of the cord. Upper
slat 23 can be used for mounting the curtain and pull cord
25 arranyed for manipulation in the manner described
below for the embodiment of Figure 3.
In the preferred embodiment, the length of the
slats corresponds substantially to the width of the curtain
and the width of the slats corresponds substantially to
the width of the thin-film strips from which the curtain
is made. The full length and width of the strips are
thereby sandwiched between the slats when the tubes are
collapsed~ Accordingly, when fully expanded, the trans-
verse width o~ the tubes is substantially less than the
width of the slat. In the embodiment of Figure 1, the
side sections of each tube have a width of about one-half
the width of mid sections such that the width of slats 23
and 24 is about twice that of the mid sections~ For
purposes of illustrating the effect of changing those
dimensions, different relative dimensions of the corres-
_g_
)9Sl
ponding parts are shown in Figuxe 7. Here -the side~ r
sections are approximately e~ual -to the mid sections.
Corresponding slats shou:Ld threfore have a width about
three times the width oE the mid sections (if 14a = 14c
- 14b = 1", then 14a -~ 14b + 14c = 3").
With further reference to Fiyure 7, the row ~1
as formed has loose upper ends 21a and 21c and loose
lower er~ds may be cut of~ or used to secure the top
and bottom of the curtain -to slats 23 and 24, respectively.
The tubular cavities defined by the upper and
lower tube walls contain essentially still or dead air
since those walls preven-t any transverse movement of air.
Accordingly, where a high degree of thermal insulation
is desired, the tubes should be made of an impermeable
material of low heat conductivity. The tube material
should also be sufficiently flexible for the tubes to
~ully expand under their own weight and the weight of
lower slat 24 and of a durabi]ity allowing repeated
flexure without cracking or other deterioration. A good
grade of thin polyethylene or equivalent plastic sheeting
will satisfy these requirements~
Each side of the tubular cavity is a composite
of two side sections, one :Erom the upper and the other
Erom the lower tube wall. The side bands joining those
two sections form fold lines along each side of the
tubular units makiny up the curtain. The double wall
thickness and the adhering material at the sideband juncture
provide reinforcement of the tube structure at the poin-t
of grea-test stress and wall flexure.
--10--
/
Another embodimen-t of the inVention is illustra-ted
in Figures 2, 3 and 9, the overall structure being gener-
ally designated 30 and the curtain por-tion thereof C2.
Curtain C2 is comprised of a plurali-ty of tube rows 31, r
32, 33, 34 and 35, one adjoining the other in the direc-tion
of curtain thickness. Each row is comprised of a plurality
of superimposed tubes having the same structure as the
tubes in row Cl of Figure 1.
The bands of adhering contact between superimposed
strips have been assigned a designation corresponding to
the bands of adhesive applied when making the curtain as
described later with reference to Figure 4. Referring
now to Figures 2 and 9, the superimposed tubes of row
31 are joined together by bands of contact Al, the tubes
of row 32 by bands B2, the tubes of row 33 by bands A2,
; the tubes of row 34 by bands B3, and the tubes of row
35 by bands A3. These bands form the mid sections of
the correspondin~ tubes. The upper and lower side sections
of tubes 31 are joined together on opposite sides of
each tubular cavity by bands of contact sl and s2, the
side sections of tubes 32 by bands Al and A2, the side
sections o~ tubes 33 by bands B2 and B3, the side sections
of tubes 34 b~ bands A2 and A3, and the side sections of
tubes 35 by bands B3 and B4. As evident from the foregoing,
those bands intervening between the outer vertical walls
40 and 41 of curtain C2 serve both as a band of contact
~oining the side sections of the tubes in an adjacent row.
Bands inside of outer tube rows 31 and 35 join the side
sections of two adjacent rows, one at each edge of the
adjoining band. For example ! band B2 adheringly secures
superimposed tubes 32 one atop -the other in the direction
of curtain height and also adheringly secures the upper
and lower side sections on one side of tubes 33. As
explained with reference -to curtain Cl, the bands adjoining
the side sections of each tube define fold lines for the
collapse and expansion of that tube and the curtain as a
whole. The tubes therefore collapse into a symme-trical
stack S when compressed together as illustrated in Figure
3. In Figure 3, there is shown a pair of pull cords 50
and 60 and corresponding pulley mechanisms 51 and 61
for manipulating the multirow tubular curtain C2. Pull
cord 50 passes over a pulley 54 and down through a series
of apertures 52 in a support sla-t 42, a movable slat 44
and the intervening tubes of center tube row 33. The
end of pull cord 50 is secured to the movable slat ~4 by
a knot or other fastening means as seen in Figure 2,
Pulley 54 is rotatably mounted upon a shaft 55 supported
by a pair of brackets 56-56 which may be secured to mount-
lng slat 42 by screws 57 or the like. In a similar manner,
pull cord ~0 passes over a pulley 64 and through apertures
62 and is secured to movable slat ~4 and 63. Pulley
64 is rotatably mounted upon shaft 65 supported by a pair
of brackets 66-66 which are secured to slat 42 by screws
67 or the like.
The slat 42 may be mounted in a ~indow, doorway or
other opening by means of eyebolts 68 or other mounting
brackets which may be positioned at each corner of the
mounting slat as illustra-ted in Figure 3. Mounting
-12-
~L~9~
eyebolts 68 cooperate with hooks or other coopera-tiny
fastners (no-t shown) as can be mounted along the top of
a fxame around the opening or on adjacent structure, such
as a ceilin~.
The manner in which curtain ~2 is attached -to end
slats 42 and 44 will now be described. With reference to
Figure 9, cur~ain C2 is pxeferably made without any
adhering material on the upper surface of uppermost strip
38 or on the lowermost surEace of lowermost strip 39O This
leaves a series of unadhered upper sections 38a, 38b, 38c
and 38d and unadhered lower sections 39a, 39b, 39c and
39d. These may be left along or cut as illustrated by the
cut line K through the lower sections. Although the end
strips can be secured to the slats in the shape shown in
Fi~ure 9, it is preferable to attach those strips in a
flattened state so that a neatly folded stack S will be
produced when the curtain is collapsed. sefore attachment~
the side sect~ons 38a and 38d and 39a and 39d are pulled
transversely apart in the direction of curtain thickness
causing the uppermost and lowermost tubes of rows 32 and
34 and some adjacent tubes to flatten as seen in areas
D and D' o~ Figure 2. The flaktened upper an~ lower
surfaces are then secured to the correspondin~ slats by
an appropriate means of attachment, such as a layer of
adhesive. Staples, nails and similar means of physical
a-ttachment can also be employed. When the curtain is
so secured, the distortion in areas D and D' is relativel~v
minor and dampens out within a few tubes of the end of each
row so t;hat the major intervening por-tion of the curtain
~13-
~.
5 1
expands into a symmetrical undistorted shape of attractive
appearance.
The width of -the side sections and mid sections
of each tube will again determine the width of the slats
to be used wi-th the curtain. The slat width is, of course,
also a function of the number of tube rows making up -the
curtain. Preferabl,v, the number of rows and the section
widths are chosen so that the collapsed thic]~ness does not
exceed twice the fully expanded thickness of the curtain.
Where the curtaln consists of five tube rows as shown, the
width of each side section should be about l/2 the mid band
width. Thus lf the mid band width is l" and the side
~` section width is 1/2", the thickness of the fully expanded
curtaln will be about 5" and the slat width should be
` about 8" (S mid bands = 5", 6 side sections = 3" and
5" ~ 3" = 8"). These relative dimensions appro~imate
those illustrated in Figures 2 and 3. For purposes of
illustrating the effect of those dimensions, the side
sections shown in Figure 9 have a width about equal to
that of the mid bands. If the outermost bands Bl and B4
are to be included between the slats, the slat wid~h should
be increased by those increments.
The method of making the tubular curtain of the
present invention will now be described. With reference
.
to Figure 4, a first supply roll 80 and a second supply
roll 90 provide continuous strips 82 and 92 of thin~film
material, preferably thin sheets of plas~ic. Strip 82
passes through an upper adhesive station A comprise~ of
a guide roller 83 for tensioning and directing the strip
-14-
,~__ - . . ____ _.. ._
over a series of applicator wheels ~ 2, ~.3 and M~
mounted for rotation upon a shaEt 850 The applicator
wheels M contac-t the undersi.de of strip 82 and underlying
those wheels is a pick-up roller 86 mounted Eor rota-tion
partially suhmerged in an aclhesive contained in a trough
88.
Strip 92 passes through a lower adhesive station
B comprised of a guide roller 93 for tensioning and
directing the strip over a series of applicator wheels
Nl, N2, N3, N4 and N5 mounted for rotation upon a shaft
95. The applicator wheels N contact the underside of
strip 92 and underlying those wheels is a pick-up roller
9G mounted for rotation partially submerged in an adhesive
: contained in a trough 98. After passing through the
adhesive stations, strip 92 is interleaved beneath strip
82 and the two strips wound simultaneously upon a forming : ~.
. member, generally designed F. It is to be understood that
the supply rolls, the rollers and wheels of the adhesive
stations, and the forming member are suitably mounted for
rotation relative to each other, and that the forming
member is driven by conventional machinery to wind the
continuous guide strips 82 and 92 thereon in interleaved
fashion. Guide rollers 83 and 93 maintain sufficient
tension on the strips -to produce a flat even stack of
superlmposed strips around -the periphery of the forming.
member.
The forming member is shown as a cylindrical drum
lO0 for purposes of illustration. The forming member may
take other shapes capable of providing a continuous
-15-
9~1
winding surface about their periphery. For example, the
member may be comprised of an endle~s belt supported upon
two or more drums or rollers as shown in U. S. Patent No.
3,963,549.
The manufacturirlg process is initiated by detachably
fastening the end of strip 92 to the periphery of the
forming member F by means o~ clamping devices (not shown)
so that movement of the periphery in the direction of
arrow Q will pull the strip ~rom the supply roll and
~; 10 ~ through adhesive station B. Strip 92 is attached to the
forming member approxlmately a-t location T. The end of
:
strip 92 is pulled around once and then the end of strip
82 is attached at approximately the same location by
means o~ a second clamping device (not shown). Adhesive
' stations A and B are then placed in posltion for appli-
~` cation o the adhesive to each strip. As strip 82 is
pulled through station A, rolle~r 86 picks up adhesive from
trough 88 and supplies it to the set of applicator wheels
; M which in turn apply the adhesive to the underside of the
~ strlp ln a plurality of narrow transversely spaced bands
extending longitudinally along the strip length, bands
,
1, A2, ~3 and ~4 being~applied by applicator wheels Ml~
M2, M3 and M4, respectively.
As strip 92 is pulled through station B, roller
96 picks up adhesive from trough 98 and supplies it to
the set~of applicator wheels N which in turn apply the
adhesive to the underside of the strip in a plurali-ty of
narrow transversely spaced bands extending longitudinally
along the strip length, bands Bl, B2, B3, B4 and B5 being
applied by applicator wheels Nl, N2, N3, N4 and N5,
respectiyely,
-16-
After application of the adhesive bands, the s-trips
are wound in interleaved fashion arouncl the periphery of
the forming member to produce bands of contact adheringly
securing each strip to the next superimposed strip. The
upper set oE adhesive bands A is offset -transversely
relative to the lower set of adhesive bands B as viewed
from lef-t to right in Figures 4 and 5. This offset be-tween
adhesive bands A relative to adhesive bands B staggers the
~; bands of adhering contact between successive strips. Thus,
-the transverse distance between adjacent bands on opposite
sides of the same strip substantially defines the width of
the unadhered side section of each tube wall. It is this
stagyered relationship that produces the expanded curtain
structures shown in Figures 6 through 9.
This distance around the periphery of the forming
member is preferably equal to or a multiple of the width
of the curtains to be made. When the number of windings
on the forming member will produce the desired height of
-the curtain in its e~panded state, the winding operation
is stopped and the wound stack of tubes cut transversely
along a line X X' shown in Figure 4. A single cut produces
a curtain width equal to the circumferential distance.
Multiple cuts corresponding to the number of curtain wid-th
multiples making up the circumferential dis-tance will
produce the corresponding number of curtains, The first
cut line X-X' is pleferably over -the location a-t which
adhesive was first applied to the firs-t layer of strip
82. The distance between that location and the point of
attachment T is determined by the distance between the
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~6~
adhesive stations and the point of attachment, that being
the distance the adhesive mus-t -travel before interlamination
occurs.
After severing the strips along line X-X', the
winding is removed. Since no adhesive was placed on the
underside of the first strip of ma-terial, there is no
adhering contact between -that strip and the underlying
supporting surface and the winding is easily pulled away
from the forming member after cutting. Upon removal, the
strips are straightened into a linear stack. With reference
to Figure 5, a plurality of adjoining tube rows 31, 32,
33, 34, 35, 36 and~37, each comprised of a plurality of
tubes superimposed one atop the other, are thereby produced.
The number of tube rows produced is such tha-t a
plurality of curtains oE the same he1ght and width but
having difering numbers of adjacent rows can be made
simultaneously as illustrated by the cut lines Y and Y~ oE
: :1
Figure S~ Two cut lines are employed to minimize the width
of resulting side bands B4 and B4l. ~Longitudinal cuts are
preferably made through the adhering bands of contact to
: : : .
maintain the integrity of tube walls on both sides of the
cut line. The two resu-ting segments form the curtain C1
of Figure 6 Which has a single row of tubes and the curtain
C2 oE Figure 8 wh1ch has five rows of tubes, one adjoining
the other in the direction of curtain thickness.
The segment of Figure 6 is shown fully expanded
in Figure 7. The segment of Figure 8 .LS shown Eully expanded
in Figu~e 9. As previously indicated, there is no adhesive
material on the upper surface of strip segments 21 and 38 or
~18-
B~5~
the lower surface of strip segments 22 and 39.
The foregoing specific embodimen-ts are merely
exemplary of the various embodiments possible and the true
scope o~ the invention is not to be limited to those embodi-
ments but is defined by the clalms a-t -the end of this
specification. Other embodiments and modifications of
both the product and method of the invention will be
apparent to those skilled in the art from consideration of
; the disclosure as a whole.
For example, the adhering bands of contact between
the strips can be produced by means other than adhesive
coatin~s, such as by thermal or solvent melding of the strip
material. Furthermore, the tube wall midsections need not
be coextensive with the bands of contact. Instead, the
bands may be interrupted along their length or consist of
two narrow strips along each edge of the midsec-tion. The
bands of contact may also be reinforced with longitudinal
braces of resilient material laminated between the ~all
midsectlons along with -the adhesive. The mid bands may also
be spaced transversely from the side bands by une~ual
distances~or offset from each other to produce tubular
cavities of varying shapes when in the expanded sta-te.
Other modifications to the bands of contact can
be made and are within the contemplation of this invention,
Thus, the bands need not be parallel but can follow other
rela-tive courses down the lenyth of the strips. Such bands
can be produced by relative movement between the applicator
wheels of -the adhesive stations. The wid-th of each band
may also be varied across the width of the strip by varying
--19--
~ ~8~95~
the thic]sness of the applicator wheels in each se-t. Similarly,
an applicator wheel of varying thickness about its circum-
ference will produce a band of varying thickness wi-th
non-parallel sides. Where the bands of contact include an
adhesive coating, the coa-ting may con-tain pigments causing
it to either absorb or reflect heat and light. Similarly,
while the strips are preferably of a transparent or trans-
lucent material, they may include light absorbing or ligh-t
reflective ma-terial.
The lnterlaminated stack of strips is rapidly
produced on the forming member through the use of multiple
strip sources. Although multiple adhesivé stations are
shown in Figure 4, it is to be understood that a single
adhesi~e station may apply bands to each side of a single
strip with the bands on one side being spaced transversely
in staggered relation to the bands on the opposite side,
Where adhesive bands are applied on opposi~e sides of the
same strip, a strip without adhesive is interleaved between
each adhesive strip to produce the staggered tubular
structure illustrated in the drawings. As another modifi-
cation, a single s-trip can be wound with bands applied
alternately to opposite sides in the staggered relationship
re~uired, each set of bands extending for one revolution
of the forming member.
The uppermost and lowermost strips of the curtain
may be oE a sheet material thicker than the in-tervening
s-trips ~orming the body of the curtain. Similarly, the
outer edges of each strip may be thic]ser than the central
portion. Such increases in thic]sness ~ould provide
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~ 1 ~ 69`~
reinforcement for those parts of the curtain subject to
greatest stress and the most wear and tear.
A number of other modifications usable with the
present invention appear i.n U. S. Patent Nos. 3l963!549 and
~,019,55~-
.
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,. . .
