Method and apparatus for forming an expandable-collapsible article having a contoured surface

A method and apparatus for forming expandable-collapsible articles comprises a horizontally oriented frame which receives one or more webs of sheet material from a feeding mechanism, a pusher bar having upper and lower gripper members engageable with the sheet material and a stripper bar having upper and lower stripper members movable between folding position and discharge position with respect to the frame. One or more linear actuators are provided to move the pusher bar toward and away from the stripper bar, and the extent of linear movement of such actuators is adjustable so that different lengths of sheet material can be advanced by the pusher bar into contact with the stripper bar thus forming fold lines in the sheet material with varying spaces therebetween. An expandable-collapsible product is formed having an accordion fold configuration with an outwardly facing surface of essentially any desired contoured shape, or, alternatively, cellular articles are formed consisting of a series of side-by-side, elongated hollow cellular units which are formed by the same elements used in fabricating accordion folded articles, with the addition of adhesive dispensers and welding units.

FIELD OF THE INVENTION 
This invention is related to a method and apparatus for forming 
expandable-collapsible articles, and, more particularly, to a method and 
apparatus capable of forming pleated and/or cellular units for use as 
window treatments, filters and the like in which at least one surface 
formed by the interconnected pleats or cellular units has a contoured 
appearance. 
BACKGROUND OF THE INVENTION 
Expandable-collapsible products for use as window shades, filter media and 
similar articles have been manufactured in a variety of configurations by 
a number of different methods and apparatus. One type of 
expandable-collapsible product is a zig-zag or accordion folded article 
comprising a series of interconnected pleats such as disclosed, for 
example, in U.S. Pat. Nos. RE 27,094; 4,181,070; 3,921,432; 4,012,932 and 
others. Another type of construction is the so-called "honeycomb" or 
cellular structure wherein selected folded portions of one or more sheet 
materials are interconnected by adhesive or the like to form side-by-side, 
elongated hollow channels. Patents illustrative of honeycomb type 
expandable-collapsible products include U.S. Pat. Nos. 4,603,072; 
4,631,108; 4,685,986; 4,631,217; 4,676,855; 4,677,012; and 4,677,013. 
The pleated, accordion folded articles, and the honeycomb or cellular 
products noted above, are formed with a variety of different devices 
depending upon the particular configuration of the finished article 
desired and how various folds of the sheet materials forming the article 
are interconnected. The formation of the folds themselves in the sheet 
material requires a separate process step within a product fabricating 
system, or with a stand-alone unit, when forming either type of article 
noted above. 
One method and apparatus for folding sheet material involves the use of 
cooperating rollers having intermeshing teeth. The teeth engage and fold 
the sheet material therebetween in the course of passage through the 
rollers. See, for example, U.S. Pat. Nos. 4,811,873; 4,871,006; and 
5,193,601. Another type of folding apparatus employs a pusher bar which is 
horizontally movable toward and away from a vertically movable stripper 
bar. The pusher bar engages one or more sheets of material positioned atop 
the frame of the folding apparatus, and advances that portion of the sheet 
material between the pusher bar and stripper bar toward the stripper bar 
against which the sheet is folded. The stripper bar is moved vertically 
upwardly after the fold has taken place to allow the pleat just formed to 
move downstream, while the pusher bar is returned to its initial position, 
spaced from the stripper bar, in preparation for another folding 
operation. Apparatus of this general type are disclosed, for example, in 
U.S. Pat. Nos. 2,387,163; 2,495,130; 4,201,119; 4,871,404; 4,943,454; and 
5,205,891. 
One limitation of each of the methods and apparatus described above is that 
the resulting accordion folded article, and/or cellular article, has a 
planer surface. That is, the "peaks" or fold lines of the interconnected 
pleats forming the accordion type of expandable-collapsible article all 
lie in the same plane because all of the pleat heights are the same. This 
is also true for expandable-collapsible cellular articles made of a series 
of interconnected cellular units since the height or transverse dimension 
of each "cell", e.g. elongated hollow channel, is the same throughout the 
article. While expandable-collapsible articles having a planer surface are 
suitable for some applications, they are of limited aesthetic interest 
when used to form window treatments and the like, and are less than 
desirable in a variety of filtering applications. 
SUMMARY OF THE INVENTION 
It is therefore among the objectives of this invention to provide a method 
and apparatus for forming an expandable-collapsible article which has at 
least one outwardly facing, contoured surface, which is capable of forming 
both pleated, accordion folded articles and cellular articles, which is 
capable of varying or maintaining consistent the pleat height or cell 
height of each type of article, which is essentially completely automatic 
in operation, and, which produces pleated or cellular articles having 
precise dimensions. 
These objectives are accomplished in a method and apparatus for forming 
expandable-collapsible articles comprising a horizontally oriented frame 
which receives one or more webs of sheet material from a feeding 
mechanism, a pusher bar having upper and lower gripper members engageable 
with the sheet material, a stripper bar having upper and lower stripper 
members movable between a folding position and discharge position with 
respect to the frame, and, a pre-creaser bar located between the pusher 
bar and stripper bar. One or more linear actuators are provided to move 
the pusher bar toward and away from the stripper bar, and the extent of 
linear movement of such actuators is adjustable so that different lengths 
of sheet material can be advanced by the pusher bar into contact with the 
stripper bar thus forming fold lines in the sheet material with varying 
spaces therebetween. An expandable-collapsible product is thus formed 
having an accordion fold configuration with an outwardly facing surface of 
essentially any desired contoured shape. Alternatively, cellular articles 
can be formed by the apparatus of this invention consisting of a series of 
side-by-side, elongated hollow cellular units which are formed by the same 
elements used in fabricating accordion folded articles, with the addition 
of adhesive dispensers and welding units. 
One aspect of this invention is predicated upon the concept of providing an 
adjustable drive mechanism for the pusher bar which is capable of varying 
the position of the pusher bar with respect to the stripper bar in 
essentially any sequence, at any time during the operation of the 
apparatus. In the presently preferred embodiment, linear actuators such as 
ball and screw mechanisms are mounted at opposite ends of the pusher bar 
and are driven by one or more variable speed stepper motors whose 
operation is controlled by a programmable controller such as a personal 
computer. Depending upon the requirements of a particular application, the 
linear actuators are operative to position the pusher bar at essentially 
any distance, within a predetermined range, with respect to the fixed 
position stripper bar. Consequently, the length of the sheet material(s) 
between the pusher bar and stripper bar can be varied as desired, and in 
any given sequence. 
This capability of the subject invention enables articles to be formed 
having a contoured or nonplaner outer surface of essentially any 
configuration. For example, zig-zag or accordion folded articles have a 
pleat height which is defined as the distance between two adjacent 
foldlines, i.e. from "peak-to-peak". Because the linear actuators which 
move the pusher bar are capable of adjusting the position of the pusher 
bar with respect to the stripper bar at the beginning of each successive 
folding operation, the distance between adjacent folds can be adjusted as 
desired, thus altering the pleat height from one pleat to another in any 
sequence within a predetermined height range. The pre-creaser bar assists 
in the folding operation by moving vertically upwardly into engagement 
with the sheet material between the pusher bar and stripper bar, thus 
forming a "bow" or pre-crease in the sheet material immediately in advance 
of the linear movement of the pusher bar to the stripper bar. The "outer 
surface" of the resulting article, e.g. the surface defined by adjacent 
peaks in the series of interconnected pleats, therefore has a non-planer 
or contoured shape which provides finished products such as window shades 
with an aesthetically distinctive appearance. 
In the presently preferred embodiment, linear actuators are also provided 
to move at least one of the upper and lower gripper members of the 
stripper bar with respect to the other between a closed gripping position 
in which the gripper members engage one or more webs of sheet material 
therebetween, in preparation for movement to the stripper bar to form a 
fold, and a spaced position in which the gripper members disengage the 
sheet material allowing the pusher bar to return to an initial contact or 
gripping position in preparation for another folding operation. Similarly, 
linear actuators are employed with the stripper bar to move the upper and 
lower stripper members relative to one another between a closed, folding 
position for engagement with the sheet material and pusher bar, and a 
separated or discharge position which allows the pleat or cellular unit 
which has just been formed to pass downstream along the frame of the 
apparatus for further handling. Adjustment of the vertical movement of the 
upper and lower gripper members of the pusher bar, and the upper and lower 
stripper members of the stripper bar, is obtained by operation of the 
linear actuators associated therewith to accommodate sheet materials of 
different thickness. 
Another aspect of this invention involves the use of the apparatus herein 
to form a cellular expandable-collapsible product in which a series of 
interconnected, side-by-side cellular units are formed, each of which is 
multi-sided and has an elongated hollow interior or core. The same pusher 
bar and stripper bar are employed as described above, with the addition of 
dispensers for applying adhesive, and one or more ultrasonic or laser 
welding units carried by the pusher bar. 
In the presently preferred embodiment, two webs of sheet material are fed 
onto the frame of the apparatus, one on top of the other, such that each 
sheet has an exposed surface. A first adhesive dispenser applies 
longitudinally spaced beads of adhesive, each extending along the width of 
the exposed surface of one sheet, and a second adhesive dispenser applies 
adhesive beads on the exposed surface of the other sheet opposite the 
first adhesive beads. This adhesive dispensing step is performed upstream 
from the pusher bar where the ultrasonic or laser welding units are 
mounted. Such welding units are activated as the upper and lower gripper 
members of the pusher bar engage the two webs of sheet material, and they 
form an essentially continuous weld line along the width of the two sheets 
adjacent, but spaced from, the two adhesive beads on the exposed surfaces 
of the sheets. The linear actuators associated with the pusher bar are 
then operated to move the pusher bar, and that portion of the two sheets 
located between the pusher bar and the stripper bar, in a direction toward 
the stripper bar. In the course of such movement, an air tube introduces a 
jet of air between the two sheets so that they are separated from one 
another prior to engagement with the stripper bar. 
A diamond-shaped cellular unit is formed each time the pusher bar and sheet 
material contact the stripper bar. Each cellular unit has opposed fold 
lines or peaks defining the overall height of the cellular unit, and 
opposed weld lines where the two sheets were interconnected by the 
ultrasonic or laser welding units. Additionally, each cellular unit has 
first and second exposed surfaces, each carrying one of the adhesive beads 
applied upstream, as described above. The other two exposed surfaces of 
each diamond-shaped cellular unit carry no adhesive. In an operation 
performed downstream from the stripper bar, the two exposed surfaces from 
one cellular unit which carry an adhesive bead are urged into engagement 
with the two surfaces of an adjacent cellular unit having no adhesive. As 
a result, small "pockets" are formed between adjacent cellular units, one 
on either side of the weld line therebetween, each comprising an 
elongated, open channel extending across the entire width of the sheet 
material. The interconnection of adjacent cellular units with beads of 
adhesive adds rigidity to the overall article, and the "pockets" provide a 
location for drawstrings to be inserted when the cellular units of this 
invention are utilized in the formation of window shades or similar 
expandable-collapsible articles. The pockets effectively hide such 
drawstrings from view and thus produce a more aesthetically pleasing 
product. 
An important advantage of the apparatus and method of this invention, when 
forming either pleated, accordion folded articles or the cellular units 
described above, is the fact that the outwardly facing surface of such 
articles can be contoured in essentially any desired configuration. As 
noted above, the linear actuators associated with the pusher bar are 
adjustable and controlled by a programmable controller so that the 
distance between the pusher bar and stripper bar in successive folding 
operations is essentially infinitely variable. The resulting folded 
articles can have varying pleat heights in the case of zig-zag or 
accordion folded articles, or variable cell heights in the case of 
cellular articles, in essentially any desired sequence depending upon the 
aesthetic or functional requirements of a particular application. At least 
one outwardly facing surface is thus formed in either type of article 
having a "contoured" appearance, wherein the fold lines forming adjacent 
peaks of the pleats or cellular units lie in at least two different 
planes. The two-piece stripper bar and pusher bar employed herein further 
increase the efficiency of operation of the system, and are adjustable to 
accommodate sheet materials of varying thickness.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to FIGS. 1 and 2, the apparatus 10 of this invention 
generally comprises two sheet feeding mechanisms 12a and 12b, an adhesive 
applicator unit 14, a pusher bar assembly 16, and, a stripper bar assembly 
18. The apparatus 10 is operative to form zig-zag or accordion folded 
articles 20 (FIG. 10), and cellular articles 22a, 22b (FIGS. 6-7), as 
explained in more detail below. The following discussion will describe 
each of the system elements individually, followed by an explanation of 
the operation of apparatus 10 in forming the articles 20, 22a and 22b. 
Sheet Feed Mechanisms 
The sheet feed mechanisms 12a and 12b depicted schematically in FIG. 1 form 
no part of this invention of themselves, and therefore the details of the 
operation of same are not provided herein. Such sheet feed mechanisms 12a, 
12b are commercially available, and are presently utilized in other types 
of apparatus for forming expandable-collapsible articles. 
For purposes of the present discussion, and with reference to FIG. 1, the 
two sheet feed mechanisms 12a and 12b include support stands 24a, b each 
having a drive roller 26. The drive roller 26 of support stand 24a mounts 
a web 28 of sheet material 29, and the support stand 24b of sheet feed 
mechanism 12b mounts a web 30 of sheet material 31. As discussed in more 
detail below in connection with a description of the method of operation 
of apparatus 10, one of the sheet materials 29, 31 is utilized to form the 
zig-zag or accordion folded article 20, whereas both sheet materials 29, 
31 are employed in the formation of cellular articles 22a and 22b. 
The drive roller 26 of each support stand 24a, b, is drivingly connected to 
a DC drive 32, which, in turn, is connected by a line 34 to a drive 
controller 36. The operation of the drive controller 36 is controlled by a 
programmable system controller 38 such as a Catec Model PSQ-8 available 
from Custom Applied Technology Corporation of Sarasota, Fla., a dedicated 
computer or other suitable controller system. As described below, the 
system controller 38 controls all functions of the apparatus 10 and can be 
programmed to form essentially any configuration of the articles 20, 22a 
and/or 22b, as desired. 
The sheet material 29 is unwound from web 28, fed around the roller 40 of a 
tensioner bar 42, and is then wrapped over a guide roller 44 from where 
the sheet material 29 extends onto the frame 46 of apparatus 10. The sheet 
material 31 from web 30 is fed in a similar manner to the frame 46, e.g. 
over the roller 48 of a tensioner bar 50, and then over a guide roller 52 
to a position beneath the sheet material 29 from web 28. As discussed 
below in connection with a description of the formation of cellular 
articles 22a and 22b, the sheet materials 29, 31 are fed one on top of the 
other along frame 46 to the pusher bar assembly 16 and stripper assembly 
18. In the formation of a zig-zag or accordion folded article 20, only one 
of the sheet materials 29 or 31 is required. 
Adhesive Applicator 
Referring now to FIG. 2, the adhesive applicator 14 is illustrated in more 
detail. As described below, the adhesive applicator 14 is only utilized in 
the formation of cellular articles 22a and 22b. It is not needed when the 
apparatus 10 is operating to form zigzag or accordion folded articles 20. 
Consequently, the discussion of the construction of adhesive applicator 14 
which follows assumes the presence of both the upper sheet material 29 and 
lower sheet material 31 atop the frame 46. 
In the presently preferred embodiment, a mounting bracket 54 is provided 
having a pair of support legs 56, 58 each connected to one side of the 
frame 46, and an upper cross brace 60 extending between the support legs 
56, 58 in a position above the frame 46 and the sheet materials 29, 31 
thereon. The upper cross brace 60 mounts a first ball and screw mechanism 
62 which extends from mounting leg 56 to the center of cross brace 60. A 
second ball and screw mechanism 64 is also mounted to the upper cross 
brace 60 so that it abuts the first ball and screw mechanism 62 and 
extends to the second mounting leg 58. The ball and screw mechanisms 62, 
64 are preferably of the type such as sold under the system Model No. 2AC, 
under the name "Powerslide", by Thomson Industries, Inc. of Port 
Washington, N.Y. Ball and screw mechanisms 62, 64 of this type include a 
rotatable, threaded shaft 68 which is mounted at opposite ends to bearings 
70, 72. The threaded shaft 68 is rotated by a reversible motor 74, 
preferably carried by one of the housings for the bearings 70 or 72. A 
carriage 76 is movable along the threaded shaft 68 in response to the 
rotation thereof, and is slidable along one or more guide rods 78 
extending between the bearing housings. 
The ball and screw mechanisms 62, 64 mount adhesive dispensers 80 and 81, 
respectively, each having a nozzle disposed immediately above or in 
engagement with the upper sheet material 29. The adhesive dispensers 80, 
81, in turn, are connected to a source of hot melt adhesive or the like 
(not shown). In response to rotation of the threaded shaft 68 of first and 
second ball and screw mechanisms 62, 64, by operation of motors 74, the 
two adhesive dispensers 80 and 81 are movable toward the center of the 
upper support plate 60, from a position adjacent the mounting legs 56, 58 
of bracket 54, thus forming an adhesive bead 84 which extends across the 
width of upper sheet material 29 as depicted in phantom lines in FIG. 2. 
When the sheet material 29 is then advanced toward the pusher bar assembly 
16 in a folding operation described below, the adhesive dispensers 80, 81 
are moved by ball and screw mechanisms 62, 64 away from one another toward 
the mounting legs 56, 58, respectively, thus applying another adhesive 
bead (not shown) onto the upper sheet material 29 at a longitudinally 
spaced location from the first adhesive bead 84. Consequently, a series of 
longitudinally spaced adhesive beads 84 are applied to the exposed surface 
of the upper sheet material 29 across the entire width thereof. The term 
"longitudinally" as used herein refers to the direction of movement of the 
sheet materials 29, 31 along frame 46, and the "transverse" or 
"perpendicular" direction refers to a direction perpendicular to the 
movement of the sheet materials 29, 31 along frame 46. 
Similar structure is employed to apply an adhesive bead 86 to the exposed 
surface of the lower sheet material 31. See also FIGS. 9-12. Third and 
fourth ball and screw mechanisms 88, one of which is shown in FIG. 2, are 
mounted to a lower cross brace 61 in position beneath the exposed surface 
of the lower sheet material 31. The lower cross brace 61 extends between 
and is mounted to the opposed legs 56, 58 of mounting bracket 54 in 
position beneath the upper cross brace 60. The ball and screw mechanisms 
88 have the same structure as described above in connection with 
mechanisms 62, 64, and the same reference numbers are thereforto employed 
to identify like structure. The carriages 76 of third and fourth ball and 
screw mechanisms 88 mount adhesive dispensers 89, one of which is shown in 
FIG. 2, in position beneath the lower sheet material 31 such that the 
nozzle of each dispenser 89, contacts or nearly contacts the exposed 
surface of the lower sheet material 31. Such adhesive dispensers 89 are 
moved toward and away from one another in the same manner as described 
above for dispensers 80, 81 associated with ball and screw mechanisms 62, 
64 so that longitudinally spaced adhesive beads 86 are applied to the 
lower sheet material 31 directly opposite the adhesive beads 84 on the 
upper sheet material 29. See FIGS. 9-12. 
The two sheet materials 29, 31 are therefore transmitted to the pusher bar 
assembly 16 and stripper bar assembly 18 with aligning, longitudinally 
spaced adhesive beads 84, 86 on the exposed surfaces thereof. Operation of 
the reversible motors 74 associated with each of the ball and screw 
mechanisms 62, 64, and 88 is controlled by the system controller 38 to 
ensure that the adhesive beads 84 and 86 are applied at the correct 
intervals along the sheet materials 29, 31 depending upon the size or 
height of the cellular articles 22a or 22b to be formed, as described in 
more detail below. ps Pusher Bar Assembly 
With reference to FIGS. 2, 3 and 5, the pusher bar assembly 16 is 
illustrated in detail. As described below in connection with a discussion 
of the operation of apparatus 10, the purpose of the pusher bar assembly 
16 is to advance a selected length of sheet material 29 and/or 31 to the 
stripper bar assembly 18 against which the folding operation takes place 
to form a pleat or a cellular unit. An important advantage of the 
apparatus 10 of this invention is that the movement of the pusher bar 
assembly 16 is adjustable, i.e. it can be moved to essentially any number 
of starting or contact positions along the length of sheet materials 29 
and/or 31, and thus initiate successive folding operations at different, 
spaced positions with respect to the stripper bar assembly 18. 
In the presently preferred embodiment, the pusher bar assembly 16 comprises 
an upper gripper member 98, and a lower gripper member 100 which is 
located vertically beneath the upper gripper member 98. As best seen in 
FIGS. 2 and 3, the upper gripper member 98 is generally L-shaped having a 
vertical plate 102 connected to a horizontal plate 104 with guide blocks 
106, 108 mounted on either side of the horizontal plate 104. These guide 
blocks 106, 108 each receive a pair of guide rods 110, 112 which extend 
downwardly therefrom to guide blocks 114, 115, respectively, mounted on 
the base plate 116 of lower gripper member 100. The base plate 116 is 
connected to a vertical plate 118, forming the same general L-shape as 
upper gripper member 98, and such vertical plate 118 is oriented in 
alignment with the vertical plate 102 of upper gripper member 98. 
The upper gripper member 98 is supported in position above the lower 
gripper member 100 by a pair of hydraulic or pneumatic cylinders 128, 130 
carried by the cross plate 126 of a mounting bracket 120 having opposed 
legs 122, 124 whose upper ends mount the cross plate 126. The lower ends 
of legs 122, 124, in turn, are connected to the base plate 116 and guide 
blocks 114, 115 associated with the lower gripper member 100. The cross 
plate 126 mounts the hydraulic or pneumatic cylinders 128, 130 in position 
such that the piston rod 132 of each cylinder 128, 130 connects to the 
vertical plate 102 of upper gripper member 98. The cylinders 128, 130 are 
operative to extend and retract their associated piston rods 132, which, 
in turn, moves the upper gripper member 98 toward and away from the lower 
gripper member 100. Such movement of the gripper members 98, 100 is guided 
by the guide rods 110, 112 extending therebetween so that in the extended 
position of piston rods 132, the vertical plate 102 of upper gripper 
member 98 engages the vertical plate 118 of lower gripper member 100 
across substantially the entire width of the pusher bar assembly 16 and 
frame 46. As discussed in more detail below in connection with an 
explanation of the operation of apparatus 10, movement of the upper and 
lower gripper members 98, 100 into engagement with one another temporarily 
clamps or grips one or both of the sheet materials 29, 31 therebetween for 
movement to the stripper bar assembly 18 in order to perform a folding 
operation. 
Opposite ends of the lower gripper member 100 are mounted on a pair of 
adjustable linear actuators 134, 136, preferably of the type sold under 
Model No. RX 102B-12-M55-MC by Industrial Devices Corporation of Novato, 
Calif. With reference to FIG. 5, each linear actuator 134, 136 includes a 
threaded shaft 140 carried by bearings 142, 144 at opposite ends, and 
having a carriage 146 movable between the bearings 142, 144 in response to 
rotation of the threaded shaft 140. The carriage 146 of each linear 
actuator 134, 136, in turn, is connected to the base plate 116 of lower 
gripper member 100, as schematically depicted in FIG. 5 and shown in FIG. 
3. 
The threaded shaft 140 of linear actuators 134, 136 each mount a bevel gear 
150, 151, respectively. Bevel gear 150 is drivingly connected to a bevel 
gear 152 mounted at one end of a shaft 153 whose opposite end carries a 
bevel gear 154 mounted in position to mesh with a drive gear 155 on the 
output shaft 156 of a stepper motor 158, preferably of the type sold under 
Model No. 583-135-MO by The Control Division of Parker Hannifan 
Corporation of Wadsworth, Ohio. The stepper motor 158 is mounted to the 
frame 46 approximately in the center thereof, e.g. midway along the lower 
gripper member 100, and is operated by a motor controller (not shown) 
connected to the system controller 38. The drive gear 155 on the output 
shaft 156 of stepper motor 158 also meshes with a bevel gear 159 carried 
at one end of a shaft 161. The opposite end of shaft 161 mounts a bevel 
gear 163, which, in turn, meshes with a bevel gear 151 on the shaft 140 of 
linear actuator 136. Preferably, each of the shafts 153 and 161 are 
rotatably supported by a bearing (not shown) at either end. 
The output shaft 156 of stepper motor 158 is rotatable both in the 
clockwise and counter-clockwise directions to precisely control the 
rotation of the threaded shafts 140 associated with each linear actuator 
134, 136 via the drive trains described above. The carriage 146 of each 
linear actuator 134, 136, and, hence, the lower gripper member 100, are 
therefore moved in an axial direction with respect to the threaded shafts 
140 and longitudinally along the frame 46. Because the upper gripper 
member 98 is connected to the lower gripper member 100 by the mounting 
bracket 120, the entire pusher bar assembly 16 is moved toward and away 
from the stripper bar assembly 18, as a unit, in response to operation of 
the stepper motor 158. 
The linear actuators 134, 136 are illustrated in the FIGURES as ball and 
screw mechanisms capable of precise, and essentially infinitely 
adjustable, linear movement in response to operation of the stepper motor 
158. It is contemplated that other "adjustable" linear actuators could be 
employed in this invention, such as hydraulic or pneumatic cylinders, so 
long as they have the capability of precisely locating and moving the 
upper and lower gripper members 98, 100 with respect to the stripper bar 
assembly 18. As described more fully below, an important aspect of this 
invention is predicated on the capability of apparatus 10 to selectively 
and precisely vary the spacing between the pusher bar assembly 16 and 
stripper bar assembly 18 by operation of the linear actuators 134, 136 so 
that different lengths of sheet material 29 and/or 31 located between the 
pusher bar assembly 16 and stripper bar assembly 18 can be folded to 
produce articles 20, 22a and/or 22b of varying size. 
The pusher bar assembly 16 also includes structure required in the 
manufacture of cellular articles 22a and 22b, as described in more detail 
below in connection with a discussion of the method of operation of 
apparatus 10. In the presently preferred embodiment, the horizontal plate 
104 of upper gripper member 98 mounts a pair of ball and screw mechanisms 
162, 164 of the same type as ball and screw mechanisms 62, 64 described 
above in connection with a discussion of the adhesive applicator 14. As 
such, the same reference numbers used in a description of mechanisms 62, 
64 are repeated in FIG. 3 to depict the same structure of mechanisms 162, 
164. 
The ball and screw mechanisms 162, 164 mount welding devices 166, 168, 
respectively, in position immediately above the exposed surface of the 
upper sheet material 29. The welding devices 166, 168 are preferably 
ultrasonic welders such as sold by the Branson Ultrasonics Corporation of 
Danbury, Conn. Alternatively, laser welding devices can be employed of the 
type sold by The Industrial Laser Source of Hopedale, Mass. The welding 
devices 166, 168 are moved by ball and screw mechanisms 162, 164 toward 
one another to the center of upper gripper member 98, and then away from 
one another to the ends thereof. A separate weld line 170 is formed during 
each of such movements of the welding devices 166, 168 which interconnect 
the sheet materials 29 and 31. See also FIGS. 9-12. 
The operation of ball and screw mechanisms 162, 164 is governed by 
controller 38 so that the welding devices 166, 168 are activated in timed 
sequence with the movement of the sheet materials 29 and 31 along frame 
46. As a result, longitudinally spaced weld lines 170 are formed along the 
length of the sheet materials 29, 31 at locations proximate the point 
where the adhesive beads 84, 86 were applied by the adhesive dispenser 
assembly 14. As discussed below, individual cellular units of cellular 
articles 22a and 22b are formed between adjacent weld lines 170, and a 
fold line is formed in the sheet materials 29, 31 midway between adjacent 
weld lines 170. 
Stripper Bar Assembly 
Referring now to FIGS. 1 and 4, the stripper bar assembly 18 comprises an 
upper stripper bar 172 and a lower stripper bar 174 which are both movable 
toward and away from one another between a folding position in which the 
upper and lower stripper bars 172, 174 contact one another (FIG. 2), and a 
discharge position where they are spaced from one another (FIG. 4). 
Vertical movement of the upper and lower stripper bars 172, 174 is 
accomplished with the same type of adjustable linear actuators 134, 136 
used in the pusher bar assembly 16. A detailed description of the linear 
actuators employed with the stripper bar assembly 18 is therefore not 
repeated herein, and the same reference numbers employed in FIGS. 1 and 3, 
are utilized in FIG. 4. 
The lower stripper bar 174 is mounted at either end to the carriage 146 of 
ball and screw mechanisms 180 and 182, which, as noted above, are 
essentially identical to ball and screw mechanisms 134, 136 of the pusher 
bar assembly 16. The carriage 146 of each ball and screw mechanism 180, 
182 is movable along threaded shaft 68 rotatably carried by bearings 142, 
144. The bearings 142, 144 of ball and screw mechanism 180 are mounted to 
one support leg 175 of a stripper bar mounting bracket 177, and the 
bearings 142, 144 of the other ball and screw mechanism 182 are mounted to 
the opposite support leg 179 of mounting bracket 177. The lower end of 
support legs 175, 179 mount to the frame 46, and the upper end thereof 
carry a cross brace 181 extending therebetween. The threaded shaft 140 of 
each ball and screw mechanism 180, 182 is drivingly connected to the 
output shaft 156 of stepper motor 158, via shafts 153, 161 in the same 
manner described above in connection with a discussion of actuators 134, 
136 and FIG. 5. The stepper motor 158 is connected to a motor controller 
(not shown) which, in turn, is connected to the system controller 38. The 
ball and screw mechanisms 180, 182 are operative to raise and lower the 
lower stripper bar 174 with respect to the upper stripper bar 172 upon 
actuation of the stepper motor 158. 
Similar structure is provided to move the upper stripper bar 172 with 
respect to the lower stripper bar 174. As shown in FIG. 4, the upper 
stripper bar 172 is carried by a pair of ball and screw mechanisms 200, 
202, which are mounted to the support legs 175, 179 of mounting bracket 
177 in the same manner as ball and screw mechanisms 180, 182. The ball and 
screw mechanisms 200, 202 have the same structure and function as ball and 
screw mechanisms 180, 182, and are given the same reference numbers in 
FIG. 4, except that another stepper motor 158 is mounted to a cross brace 
181 extending between the support legs 175, 179 of mounting bracket 177 in 
order to drive ball and screw mechanisms 200, 202. 
In the presently preferred embodiment, each of the shafts 153 and 161 are 
rotatably supported by a bearing 165 at either end. As schematically 
depicted in FIG. 1 and discussed in more detail below, the upper and lower 
stripper bars 172, 174 are movable toward one another to a folding 
position in which they contact one another to provide a surface against 
which the pusher bar assembly 18 is movable for folding the sheet material 
29 and/or sheet material 31. After a folding operation has been completed, 
the upper and lower stripper bars 172, 174 are moved to a discharge 
position, spaced from one another, to allow the pleat of article 20 or 
cellular unit of article 22 which has just been formed to move therepast. 
Pre-Creaser Bar 
With reference now to FIGS. 6 and 7, the apparatus 10 is shown in a 
configuration to form accordion folded articles 20. As described in more 
detail below, the primary operational differences in the apparatus 10 when 
forming an article 20 compared to cellular articles 22a or 22b is that the 
adhesive applicator unit 14 and welding devices 166, 168 are not needed, 
and only one of the sheet material 29 or 31 is employed. Additionally, an 
air tube 330 used in forming cellular articles 22a, b is not operated. 
Instead, the apparatus 10 is provided with a pre-creaser bar 350, located 
between the pusher bar assembly 16 and stripper bar assembly 18, which is 
effective to form a "bow" in the sheet material 29 or 31 in advance of the 
folding operation. As best seen in FIG. 7, the pre-creaser bar 350 is 
mounted to the frame 46 by a pair of ball and screw mechanisms 352, 354 of 
the same type as assemblies 180, 182 shown in FIG. 4 and described above 
in connection with a discussion of the stripper bar assembly 18. The same 
reference numbers are therefor used in FIG. 7 to depict structure 
identical to that shown in FIG. 4. 
The ball and screw mechanisms 352, 354, in response to operation of stepper 
motor 158, are effective to move the pre-creaser bar 350 vertically 
upwardly from a position beneath the sheet materials 29 or 31 to a contact 
position wherein a bow is formed in that portion of the sheet material 29 
or 31 between the pusher bar assembly 16 and stripper bar assembly 18. 
This assists the pusher bar assembly 16 in forming a pleat along the 
accordion folded article 20, as described in more detail below, and can 
also be employed to vary the heights of such pleats. Preferably, each of 
the ball and screw mechanisms 352, 354 are mounted on a track or the like 
(not shown) to permit adjustment of the longitudinal position of the 
pre-creaser bar 350 along frame 46 and between the pusher bar assembly 16 
and stripper bar assembly 18 depending upon the height of the pleats to be 
formed in the finished accordion folded article 20. 
Method of Forming Cellular Articles 
With reference initially to FIGS. 1-5, 9-12 and 14, the operation of 
apparatus 10 to form cellular articles 22 is described. As noted above, 
the apparatus 10 also can be utilized to form zig-zag or accordion folded 
articles 20 of the type shown in FIGS. 13 and 14 and a discussion of that 
operation follows. 
The formation of cellular articles 22 requires the presence of both sheet 
materials 29 and 31. The sheet feed mechanisms 12 are operated as 
described above to supply the sheet materials 29, 31, one on top of the 
other, onto the frame 46 of apparatus 10. The details of the sheet feeding 
devices and their operation form no part of this invention, and are 
therefore not described specifically herein. It should be understood, 
however, that the tensioner bars 42, 50 and other tensioning devices are 
employed, as well as other sheet feeding controls, to ensure that the 
sheet materials 29, 31 are supplied to the pusher bar assembly 16 at the 
appropriate speed and tension. 
Additionally, although not described in detail herein, the frame 46 is 
provided with heating elements (not shown) upstream from the pusher bar 
assembly 16 to raise the temperature of the sheet materials 29, 31 to a 
sufficient level so that they will take a "set" i.e. maintain their folded 
position, when the folding operation is completed. It is contemplated that 
most of the sheet materials 29, 31 worked on by apparatus 10 will include 
at least some thermoplastic material, either as a coating or contained 
within the sheet material, so that fold lines made therein are essentially 
permanent. These heating elements 47 form no part of this invention of 
themselves, and are therefore not discussed in detail herein. Such heating 
elements are commercially available and are commonly employed in a variety 
of pleat forming devices. 
An important aspect of the method of operation of apparatus 10 is its 
capability of forming cellular articles 22a and 22b of different size, and 
different shapes or contours, as desired. Before describing the specific 
operational steps involved in the formation of articles 22a or 22b, it is 
helpful to consider the finished construction of each. With reference 
initially to FIGS. 6 and 7, the cellular article 22a is depicted as 
including a number of interconnected, diamond-shaped cellular units 226 of 
the same size and shape. Each cellular unit 226 has a first side 228 which 
receives adhesive bead 84, a second side 230 to which adhesive bead 86 is 
applied, and, third and fourth sides 232, 234 which receive no adhesive. 
The first and third sides 228, 232 are separated by a fold line 236, 
whereas the second and fourth sides 230, 234 are separated by a fold line 
238. The overall height or dimension of each cellular unit 226, or 
"peak-to-peak" dimension, is constant and is defined by the distance 
between the fold lines 236, 238. This forms an outwardly facing surface 
227 of cellular article 22a having a planar appearance. 
With reference to FIGS. 10 and 12, the cellular article 22b differs from 
that of article 22a by incorporating first cellular units 240 of one 
dimension and second cellular units 242 of a different dimension. Each 
first cellular unit 240 includes first and second sides 244, 246 which 
carry the adhesive beads 84, 86, respectively, and third and fourth sides 
248, 250 with no adhesive. A fold line 252 separates sides 244, 248, while 
a fold line 254 separates sides 246, 250. The second cellular units 242 
have the same diamond-shape as the cellular units 240, but with a smaller 
height or peak-to-peak dimension between the fold lines 256, 258 which 
separate sides 260, 266 and sides 262, 264, respectively, thereof. While 
the cellular article 22b is shown with two cellular units 240 and 242, 
arranged in the pattern depicted in FIGS. 9 and 10, it will be appreciated 
that essentially any combination of cellular unit heights and patterns can 
be obtained with apparatus 10, within predetermined dimensional ranges. 
It is apparent from an inspection of the cellular units 240 and 242 within 
cellular article 22b of FIGS. 11 and 12 that the formation of same depends 
upon the proper location of the adhesive beads 84, 86, the weld lines 170 
and the fold lines 252, 254, 256 and 258 with respect to one another along 
the length of sheet materials 29 and 31. The fold lines 252, 254 must be 
centered between adjacent weld lines 170 within cellular units 240, and 
such weld lines 170 must be a sufficient distance apart to obtain the 
desired height or peak-to-peak dimension of cellular unit 240. Further, 
the adhesive beads 84, 86 must be positioned along the sheet materials 29, 
31 so that they are located on the appropriate sides 244, 246, 
respectively, of cellular unit 240 and equidistant from an adjacent weld 
line 170. The same control of the positioning of the adhesive beads 84, 
86, weld lines 170 and fold lines 256, 258 is required to form cellular 
unit 242, except the location of same is different from that of cellular 
unit 240. 
The system controller 38 is operative to control the adhesive applicator 
assembly 14, the welding devices 166, 168 and the pusher bar assembly 16 
in the appropriate intervals based upon the speed of movement of the 
sheets 29, 31 along frame 46, and the arrangement of cellular units 240, 
242 desired to obtain a given cellular article 22b having an outer surface 
260 with the desired contour or pattern. As described more fully below, 
the adhesive beads 84, 86 are applied at the desired locations along 
sheets 29 and 31 by timed operation of adhesive dispensers 80, 81 and 
adhesive dispensers 92. The welding devices 166, 168, in turn, are also 
timed by system controller 38 to form the weld lines 170 adjacent the 
adhesive beads 84, 86. Additionally, the position of fold lines 252, 254, 
256, and 258 is obtained by controlling linear actuators 134, 136 so that 
the pusher bar assembly 16 is located the appropriate distance from 
stripper bar assembly 18 at the beginning of a folding operation. 
The manner in which the system controller 38 operates to obtain cellular 
articles 22a and 22b of a desired configuration is dependent on the 
particular application. The operator has the option of programming the 
system controller 32, using a manual, keyboard interface (not shown), to 
specify the particular size and sequence of cellular units within a 
cellular article such as articles 22a, 22b. Essentially any sequence of 
different cellular units can be obtained having a size within a 
predetermined range which is limited by the extent of movement of linear 
actuators 134, 136 associated with pusher bar assembly 16. 
Alternatively, the apparatus 10 is provided with a sensor 261, connected to 
the controller 38, which is operative to produce a signal when an indicia 
263 applied to the upper sheet material 29 moves therepast. This indicia 
263 may be a special mark placed on the sheet material 29, or a portion of 
a pattern present upon the upper sheet material 29. The sensor 261 is 
located sufficiently upstream from the adhesive applicator 14, welding 
devices 166, 168, and pusher bar assembly 16 so that the controller 38 can 
function to operate the adhesive dispensers 80, 81 and 89, as well as the 
welding devices 166, 168, at appropriate intervals. Further, the 
controller 38 operates the pusher bar 16 in response to such signal so 
that fold lines 252, 254, 256 and/or 258 can be formed along the sheet 
materials 29, 31 at the required location dependent upon where the indicia 
263 is sensed by the sensor 261. 
With the foregoing in mind, the individual operations to: (1) apply 
adhesive beads 84, 86; (2) form weld lines 170, and, (3) obtain folds 252, 
254, 256 and 258, are described separately below. 
The sheet materials 29, 31 are advanced to the adhesive applicator 14 where 
their exposed surfaces receive adhesive beads 84, 86, respectively. As 
noted above, the upper adhesive dispensers 80, 81 are moved by first and 
second ball and screw mechanisms 62, 64 toward and away from one another 
in position immediately above the exposed surface of upper sheet material 
29. These adhesive dispensers 80, 81 are operative to apply the adhesive 
bead 84 onto the sheet material 29 in both directions of the movement 
thereof, i.e. while moving toward one another to the middle of mounting 
bracket 54, and away from one another toward the bracket mounting legs 56, 
58. Similarly, the adhesive dispensers 89 carried by the third and fourth 
ball and screw mechanisms 88 of adhesive applicator 14, located beneath 
the lower sheet material 31, apply adhesive bead 86 to the lower sheet 
material 31 in direct alignment with the adhesive bead 84. 
The next step in the operation of apparatus 10 to form cellular articles 
22a or 22b is to interconnect the sheet material, 29, 31 at spaced 
locations therealong. The controller 38 is effective to form 
longitudinally spaced weld lines 170, at locations along the sheet 
materials 29, 31 dependent upon the points at which the adhesive beads 84, 
86 are applied thereto. As depicted in FIGS. 9-12, the weld lines 170 are 
preferably formed along the length of sheet materials 29, 31 a 
predetermined space "S" from each of the adhesive beads 84 and 86 in both 
cellular articles 22a and 22b. The weld lines 170 are formed by operation 
of the welding devices 166, 168 carried by the upper gripper member 98 of 
pusher bar assembly 16. As discussed above, the ball and screw mechanisms 
162, 164 are operated by controller 38 to move the welding devices 166, 
168 toward one another to the center of upper gripper member 98, and then 
away from one another to its opposite ends. The welding devices 166, 168 
are operative to heat and essentially melt the thermoplastic material 
within the sheet materials 29, 31 so that they attach to one another along 
each weld line 170. Because the welding devices 166, 168 are carried by 
the upper gripper member 98 of pusher bar assembly 16, such welding 
operation is performed with the upper and lower gripper members 98, 100 in 
a gripping position, i.e. in engagement with the sheet materials 29, 31 
positioned therebetween. It is contemplated that the welding operation 
could take place at the same time as the application of adhesive beads 84, 
86 to sheet materials 29, 31, or subsequent to the adhesive application 
operation, depending upon the desired spacing between the weld line 170 
and adhesive beads 84, 86 for a cellular unit 226 of given size. 
Once the sheet materials 29, 31 have been secured together along weld lines 
170 at the desired distance from the adhesive beads 84, 86, the folding 
operation can proceed. As noted above, the fold lines 236, 238 in the 
cellular units 226 of article 22a must be centered between adjacent weld 
lines 170. Similarly, the fold lines 252, 254 of cellular units 240, as 
well as the fold lines 256, 258 of cellular units 242, must also be 
centered between their adjacent weld lines 170 in order to properly form 
the article 22b. An important advantage of this invention is that the 
position of the fold lines within cellular articles 22a, 22b, or any other 
cellular articles, can be varied in essentially any desired sequence 
during the operation of apparatus 10. The location of each fold line 236, 
238, 252, 254, 256 and 258 is determined by the distance which the upper 
and lower gripper members 98, 100 of pusher bar assembly 16 are moved with 
respect to the stripper bar assembly 18 in advance of a folding operation. 
Such distance or spacing between the upper and lower gripper members 98, 
100, and the stripper bar assembly 18, determines what portion or length 
of the sheet materials 29, 31 is advanced against the upper and lower 
stripper bars 172, 174 to form the fold lines within articles 22a and 22b. 
Precise control of the position of upper and lower gripper members 98, 100 
with respect to the stripper bar 18 is obtained by operation of the linear 
actuators 134, 136 in a manner described in detail above. 
For example, in order to form the cellular article 22a depicted in FIGS. 9 
and 10, the system controller 38 operates linear actuators 134, 136 so 
that the upper and lower gripper members 98, 100 are moved as a unit with 
mounting bracket 120 to a "contact" or gripping position relative to sheet 
materials 29, 31. This gripping position is spaced a sufficient distance 
from stripper bar assembly 18 so that fold lines 236 and 238 can be formed 
midway between adjacent weld lines 170 of one of the cellular units 226 
forming article 22a. Once properly located at such gripping position, the 
controller 38 is operative to actuate pneumatic cylinders 128, 130 of the 
pusher bar assembly 16 which moves the upper gripper member 98 downwardly 
to squeeze or clamp the sheet materials 29, 31 between the upper and lower 
gripper members 98, 100. At or about the same time, the controller 38 is 
operative to cause the upper and lower stripper bars 172, 174 to move to 
the folding position, i.e. toward and in contact with one another, to 
provide a planar surface against which that portion of the sheet materials 
29, 31 between the gripper members 98, 100 and stripper bars 172, 174 can 
be folded. The linear actuators 134, 136 are then activated to move the 
gripper members 98, 100 and sheet materials 29, 31 into contact with the 
stripper bars 172, 174 to form fold lines 236, 238. As schematically 
depicted in FIG. 2, an air tube 330 is mounted to the frame 46 in position 
between the pusher bar assembly 16 and stripper bar assembly 18 to 
introduce a stream of air in a direction transverse to the movement of 
sheet materials 29, 31 along frame 46. This air stream assists in 
separating the sheet materials 29, 31 from one another in the course of 
movement of the gripper members 98, 100 toward the stripper bars 172, 174 
to facilitate the formation of fold lines 236, 238 therein. 
After a cellular unit 226 is thus formed, the upper and lower stripper bars 
172, 174 are moved away from one another allowing the just formed cellular 
unit 226 to move therepast. Preferably, spring mechanisms (not shown) are 
provided for stripper bars 172 and 174 to urge them in a direction toward 
the gripper members 98, 100 so that the stripper bars 172, 174 can 
"clear", or move upstream from, the cellular unit 226 just formed. The 
stripper bars 172, 174 are then returned to the folding position, in 
contact with one another, in preparation for another folding operation. 
The folding operation continues as described above to form a series of 
interconnected, side-by-side cellular units 226 of article 22a. Because 
all of the cellular units 226 have the same dimension, the gripper members 
98, 100 are returned to the same gripping position at the start of each 
successive folding operation. The formation of cellular article 22b 
proceeds in the identical manner as described above, except the contact or 
gripping positions at which gripper members 98, 100 contact the sheet 
materials 29, 31 changes depending on whether a cellular unit 240 or a 
cellular unit 242 is formed. Since such cellular units 240, 242 have 
different dimensions, the gripper members 98, 100 are moved further away 
from the stripper bars 172, 174 at the beginning of a folding operation to 
form cellular units 240, compared to the gripping position required to 
properly position the fold lines 256 and 258 for cellular units 242. 
Regardless of the height or size of the cellular unit to be formed, the 
controller 38 is operative to activate linear actuators 134, 136 and 
precisely locate the gripper members 98, 100 at any contact or gripping 
position to begin a folding operation. Consequently, an article 20c such 
as depicted in FIG. 14, can be formed with a widely varying, contoured 
outer surface 370, as desired. 
FIGS. 9 and 11 depict the cellular articles 22a and 22b, respectively, as 
they appear immediately downstream from the stripper bar assembly 18. 
Cellular article 22a includes a series of side-by-side, interconnected 
cellular units 226, defined by adjacent weld lines 170, each having sides 
228-234 with the adhesive beads 84 and 86 being applied to the first and 
second sides 228 and 230, respectively. The cellular article 22b includes 
an alternating pattern of interconnected cellular units 240, cellular 
units 242 and then additional cellular units 240. 
One important use for the cellular articles 22a and 22b is in the formation 
of window shades and similar window treatments. Such application requires 
an expandable and collapsible product wherein drawstrings or cords 300 
(shown in phantom) can be employed to raise and lower the cellular 
articles 22a or 22b with respect to the window. In order to improve the 
aesthetics of such window treatments, it is desirable to hide the 
drawstrings 300 from view when looking at the outwardly facing surface 227 
article 22a, or the outwardly facing surface 260 of article 22b. This is 
accommodated in the present invention by forming upper and lower pockets 
304, 306 between the adjacent cellular units 226 depicted in FIGS. 10 and 
7, and upper and lower pockets 308, 310 in the cellular article 22b 
between adjacent cellular units 240, 242. See FIG. 9. 
With reference to FIGS. 6 and 7, each upper pocket 304 comprises an 
elongated, open channel formed between each of the adhesive beads 84 and 
the weld line 170. The lower pockets 306 are formed immediately beneath 
upper pockets 304 and extend from adhesive bead 86 to the weld line 170. 
Each upper pocket 304 is formed by forcing the first side 228 of one 
cellular unit 226 against the third side 232 of an adjacent cellular unit 
236b so that the adhesive bead 84 carried by first side 228 forms a bond 
therebetween. Similarly, each lower pocket 306 is formed immediately 
beneath an upper pocket 304 by causing the second side 230 of the cellular 
unit 226 to contact the fourth side 234 of the adjacent cellular unit 226. 
Such pockets 304, 306 are formed along the entire length of cellular 
article 22a, between adjacent cellular units 226, so that one or more 
drawstrings 300 can extend along the length of the cellular article 22a. 
The same forming step noted above is employed to form upper and lower 
pockets 308, 310 of the cellular article 22b. When interconnecting 
adjacent cellular units 240 of article 22b, sides 244, 246 of one cellular 
unit 240 carrying adhesive beads 84, 86 contact sides 248, 250 of an 
adjacent cellular unit 240. A cellular unit 240 is connected to an 
adjacent cellular unit 242 to form upper and lower pockets 308, 310 by 
engaging sides 244, 246 of cellular unit 240 with sides 264 and 266 of 
cellular unit 242. The smaller cellular units 242 are connected to one 
another to form pockets 308, 310 by forcing the sides 260, 262 of a 
cellular unit 242 carrying adhesive beads 84, 86, into contact with the 
sides 264 and 266 of an adjacent cellular unit 242. These same sides 260, 
262 of a smaller cellular unit 242 contact and bond to the sides 248 and 
250 of an adjacent, larger cellular unit 240 to form pockets 308, 310 
therebetween. It is contemplated that both cellular units 22a and 22b 
could be formed with pockets 304, 306, and 308, 310, as described above by 
squeezing the units 22a, 22b between a forming bar 312, depicted 
schematically in FIG. 2, and the stripper bar 172, 174, or by other 
suitable pressing members. 
In addition to hiding the drawstrings 300, the pockets 304, 306 of article 
22a and pockets 308, 310 of article 22b provide strength and rigidity to 
the cellular units 226, 240 and 242, and the resulting cellular articles 
22a, 22b. The weld lines 170 formed by welding devices 166, 168 may not 
provide sufficient structural integrity within the cellular articles 22a 
or 22b, particularly when they are utilized in a window treatment and are 
regularly expanded and collapsed when the window treatment is raised and 
lowered. The adhesive beads 84 and 86 overcome this potential limitation 
and ensure that the cellular articles 22a and 22b do not come apart or 
otherwise fail in a window treatment or other application. 
With reference to FIG. 8, the portion of apparatus 10 downstream from the 
stripper bar assembly is schematically depicted. This is where the 
cellular articles 22a or 22b are moved together and cured to form the 
pockets 304, 306 and 308, 310 described above. In the presently preferred 
embodiment, a belt 400 formed of stainless steel mesh or similar material 
is mounted at either end to rods 402, 404 in position to contact the 
uppermost edges or fold lines 236 of cellular article 22a and the fold 
lines 252, 256 of cellular article 22b located atop the frame 46. The 
weight of belt 400 against articles 22a, 22b is sufficient to prevent 
adjacent cellular units 226, 240 and 242 from moving apart, and it also 
increases the frictional engagement between the cellular units 226, 240 
and 242 and the frame 46. 
In order to assist in "squeezing" or urging adjacent cellular units 226 or 
240, 242 together, a retaining bar 406 is initially positioned atop the 
frame 46 against the first formed cellular unit 240, 242 (or 226). The 
retaining bar 406 is connected by a cable 408, directed over pulleys 410, 
412 mounted on frame 46, to a counterweight 414. The purpose of the 
retaining bar 406 is to exert a force against the cellular units 240, 242 
(or 226) located downstream from the stripper bar assembly 18 to urge them 
together so that the adhesive beads 84, 86 of one cellular unit 240, 242 
contact the exposed sides of an adjacent cellular unit 240, 242. The 
weight of the counterweight 414 can be varied, depending upon the size of 
the cellular units being formed, to exert the desired amount of upstream 
force against the "stack" or group of cellular units being formed. 
The stack of cellular units 226 and retaining bar 406 proceed into an oven 
416 of the type commercially available from R & K Machine Corp. of 
Sarasota, Fla. The oven 416 is effective to heat the hot melt adhesive 
beads 84, 86 to a sufficient temperature to form a bond between adjacent 
cellular units 240, 242 (or 226), thus forming pockets 308, 310. The 
pockets 304, 306 of cellular article 22a are formed in the same manner. 
Once the retaining bar 406 reaches the end of oven 416, it falls into a 
recess 418 within frame 46 and extends substantially flush with the upper 
surface of frame 46. By this time, a sufficient number of cellular units 
240, 242 (or 226) have been formed downstream from the stripper bar 
assembly 18 such that a force is exerted in a downstream direction against 
all of the cellular units 240, 242 (or 226) atop frame 46. In other words, 
the sheer number and frictional engagement of the stack of cellular units 
240, 242 atop frame 46, assisted by the weight of belt 400, is sufficient 
to cause adjacent cellular units 226 to contact one another as soon as 
they are formed and move past the stripper bar assembly 18. As a result, 
finished cellular articles 22a and 22b as shown in FIGS. 10 and 12 are 
formed within the oven 416 and are discharged from the end of frame 46. 
Method of Forming Accordion-Folded Articles 
The zig-zag or accordion folded articles 20 and 20a depicted in FIGS. 13 
and 14 are formed in essentially the identical manner described above in 
connection with cellular articles 22a and 22b, except the adhesive beads 
84, 86 and weld lines 170 are eliminated. Further, only a single sheet 
material 29 or 31 is required, and, preferably, a pre-creaser bar 350 is 
employed to assist in the folding operation. As noted above, the 
pre-creaser bar 350 is located between the pusher bar assembly 16 and 
stripper bar assembly 18, and is effective to move upwardly into contact 
with a sheet material 29 or 31 in advance of movement of the upper and 
lower gripper members 98, 100 into contact with stripper bars 172, 174 so 
that a "bow" or pre-fold is made in such sheet material 29 or 31 before 
the fold line is formed. The operation of apparatus 10 is otherwise 
similar, including movement of the upper and lower gripper members 98, 100 
of pusher bar assembly 16 and movement of the stripper bars 172, 174 of 
stripper bar assembly 18. As schematically depicted in FIGS. 13 and 14, 
the resulting zig-zag or accordion folded article 20 is formed with a 
series of side-by-side pleats 316, 318, or a variety of different pleats 
as in article 20a, having the same or a variety of different heights in 
essentially any predetermined sequence. Such sequence is either programmed 
into the system controller 38, or is determined by indicia 263 as 
described below, so that the controller 38 operates the linear actuators 
134, 136 to locate the upper and lower gripper members 98, 100 of the 
pusher bar assembly 16 at the desired contact or gripping position at the 
beginning of each successive folding operation. Consequently, an accordion 
folded article 20 or 20a can be produced having an outwardly facing 
surface 320 or 370 with essentially any contoured outer surface, or a 
planer outer surface, as desired. 
It is also contemplated that an accordion folded article 20, 20a or the 
like can be formed with varying pleat heights using the pre-creaser bar 
350 alone, or in combination with the pusher bar assembly 16. Because the 
pre-creaser bar 350 is movable in response to the operation of ball and 
screw mechanisms 352, 354, its vertical position with respect to a sheet 
material 29 or 31 moving thereabove can be varied, as desired. With the 
upper and lower stripper bars 172, 174 in contact with one another, thus 
clamping or gripping a sheet material 29 or 31 therebetween, and the upper 
and lower gripper members 98, 100 of pusher bar assembly 16 spaced from 
one another, movement of the pre-creaser bar 150 vertically upwardly 
causes a "bow" to form in the sheet material 29 or 31 which pulls or draws 
a greater length of sheet material 29 or 31 between the pusher bar 
assembly 16 and stripper bar assembly 18 than would be present if the 
sheet material 29 or 31 were flat therebetween. In other words, a portion 
of the sheet material 29 or 31 is effectively pulled or drawn downstream 
toward the stripper bar assembly 18 because of the bow formed by the 
pre-creaser bar 350. The portion or length of sheet material 29 or 31 
drawn downstream is variable, depending upon the extent of vertical 
movement of the pre-creaser bar 350, as governed by ball and screw 
mechanisms 352, 354. Consequently, when the pusher bar assembly 16 is 
thereafter operated to grip the sheet material 29 or 31 and move it into 
contact with the pusher bar assembly 18, different size pleat heights can 
be formed depending upon the extent of vertical movement of the 
pre-creaser bar 350, and, hence, the length or amount of sheet material 29 
or 31 pulled or drawn downstream by the pre-creaser bar 350. 
It is further contemplated that the above-described method of varying pleat 
height within an accordion folded article by adjusting the vertical 
movement of pre-creaser bar 350 could be done independently, or in 
combination with, variable movement of the pusher bar assembly 16. That 
is, variable pleat heights can be obtained by varying the extent of 
vertical movement of pre-creaser bar 350 while successively moving the 
pusher bar assembly 16 to the same gripping position relative to the 
stripper bar assembly 18, or, alternatively, by varying both the 
positioning of the pre-creaser bar 350 and the contact position of the 
pusher bar assembly 16 along the sheet material 29 or 31 as described 
above. In either instance, an accordion folded article is produced with 
varying pleat heights. 
While the invention has been described with reference to a preferred 
embodiment, it will be understood by those skilled in the art that various 
changes may be made and equivalents may be substituted for elements 
thereof without departing from the scope of the invention. In addition, 
many modifications may be made to adapt a particular situation or material 
to the teachings of the invention without departing from the essential 
scope thereof. 
For example, the pusher bar assembly 16 depicted in the FIGURES. is shown 
with upper and lower gripper members 98, 100. It is contemplated, however, 
that one of the gripper members 98 or 100 could be eliminated so that a 
single plate or gripper member would be employed to advance one or both of 
the sheet materials 29, 31 into engagement with the stripper bars 172, 174 
if desired. Additionally, the stripper bar assembly 18 could be formed 
with a single upper or lower stripper bar 172, 174 without departing from 
the scope of the invention. Further, while both of the stripper bars 172, 
174 have been described as being movable in a vertical direction, it is 
contemplated that the lower stripper bar 174, for example, could be 
maintained in a fixed position while only the upper stripper bar 172 would 
be moved vertically with respect thereto. 
It is also contemplated that the adhesive beads 84, 86 applied by the 
adhesive applicator assembly 14 could be continuous or discontinuous 
across the width of sheet materials 29, 31, as desired, so long as the 
resulting articles 22a and 22b retain their structural integrity. 
Additionally, while the welding devices 166, 168 are shown in the FIGURES. 
as being mounted to the pusher bar assembly 16, it is contemplated that 
they could be mounted on separate structure and/or to the adhesive 
applicator assembly 14, as desired. 
It is also considered within the scope of this invention to employ 
apparatus 10 solely as a folding device for cellular articles without the 
operation of the adhesive applicator assembly 14 or welding devices 166, 
168. It is contemplated that the sheet materials 29 and 31 could be 
interconnected along weld lines 170, and provided with adhesive beads 84, 
86, on a separate piece of equipment and then collected in rolls. These 
rolls would then be mounted to the feed mechanism 12 of apparatus 10, and 
the folds would be formed by operation of the sensor 261 picking up an 
indicia on the sheet materials 29 or 31, such as an adhesive bead 84, so 
that the controller 38 could operate pusher bar assembly 16 accordingly, 
in the manner described above. 
Therefore, it is intended that the invention not be limited to the 
particular embodiment disclosed as the best mode contemplated for carrying 
out this invention, but the invention will include all embodiments falling 
within the scope of the appended claims.