Sheet production system with hem expander

Sheet material is taken from a supply, moved along its length to a cutting station, the sheet material is cut into segments, and the cut segments are moved parallel to their cut edges, the cut edges are hemmed, and the segments are folded. At the cutting station the leading portion of the sheet material is gripped and pulled from the entrance to the cutting station to the other side thereof, a slack bar is moved downwardly into the segment of sheet material in the cutting station to form slack in the segment, and the segment in the cutting station is clamped against parallel conveyor tapes. A cutting disc is drawn across the sheet material at the entrance to the cutting station, and the parallel conveyor tapes move the sheet parallel to its cut edges to a hemming station where the edges are folded and hemmed. The hems of the side edges are expanded after being mechanically formed and prior to being sewn. The leading and trailing edges of the folded portions of the hems are aligned with the leading and trailing edges of the unfolded portion of the hem as the segment approaches the sewing machine.

TECHNICAL FIELD 
This invention relates to the manufacture of bed sheets and other sheet 
material wherein sheet material is moved from a supply along its length to 
a cutting station, the sheet material is cut into segments, and the cut 
edges of the segments are hemmed as the segments are moved along a path 
parallel to their cut edges. 
BACKGROUND 
In the production of sheet material, such as bed sheets, curtains, bed 
spreads, etc., the goods usually are cut from a supply of sheet material 
and the cut edges are hemmed. In some situations the side edges of the cut 
segments of sheet material do not need to be hemmed since the side edges 
comprise a selvage of the sheet material. Thus, only the cut edges need to 
be folded and sewn into a hem. 
Various automatic machines have been developed and used for cutting and 
hemming sheet material. For example, U.S. Pat. Nos. 3,580,198, 3,640,235, 
3,772,948, 3,906,878 and 3,955,515 all illustrate systems which appear to 
be capable of automatically cutting segments from sheet material and 
hemming the cut edges of the segments. However, it is understood that the 
prior art devices have experienced some difficulty in controlling the cut 
edges of the segments of sheet material as the cut edges are being moved 
to and through a hemmer. This difficulty is increased when a large hem is 
to be formed at the cut edge of the segment of sheet material. For 
example, the large hem at the head of a bed sheet usually is visible when 
in use by the purchaser, and it is desirable to have this hem formed with 
a constant width, so that it is uniform and attractive to the purchaser. 
However, when the hem at the head of a bed sheet is formed with automatic 
hem forming equipment, it is difficult to control the wide expanse of 
folded material so as to accurately and rapidly form the hem. 
SUMMARY OF THE INVENTION 
Briefly described, the present invention comprises a sheet production 
system with a hem expansion attachment, wherein sheet material is moved 
from a supply along its length toward a cutting station, the sheet 
material is cut into segments at the cutting station, and the cut segments 
are moved parallel to their cut edges and the cut edges are folded. The 
fold at one end of the cut segment is expanded to a large size, and the 
enlarged fold is sewn to the body portion of the cut segment. 
A gripper moves across the cutting station to the entrance of the cutting 
station to grip the previously cut leading edge of the sheet material and 
then moves back across to the far side of the cutting station, pulling the 
sheet material over a pair of parallel conveyor tapes into the cutting 
station. A slack bar moves down into the segment of sheet material between 
the parallel conveyor tapes at the cutting station, causing slack to be 
formed in the segment, and a clamp at the entrance of the cutting station 
grips and holds the segment in position while conveyor clamps move down 
toward the conveyor tapes to clamp the segment of sheet material against 
the conveyor tapes. A disc cutter is then drawn across the sheet material 
at the entrance of the cutting station, to cut the segment away from the 
supply of sheet material. The gripper then releases the cut segment and 
the conveyor tapes move the cut segment in a direction parallel to its cut 
edges at a high velocity on into the hem folding and expansion station. 
The cut edges of the segment are progressively folded as they move into the 
folding and expansion station, and after the cut edges have been folded, 
one folded edge portion of the cut segment is expanded to the desired 
width for the hem. The segment of sheet material is then moved at a slower 
speed on through a sewing station where the folded edge portions are sewn 
to the body of the sheet material, thus forming the hems at the head and 
foot of the bed sheet. If desired, the system can employ hem expanders for 
both hems. 
After hemming, the segment of sheet material, which is now sewn in the form 
of a final product such as a bed sheet, is folded for shipment and 
ultimate sale to the customer. 
Thus, it is an object of this invention to provide a bed sheet production 
system with a hem expander attachment, wherein the system functions to cut 
segments of sheet material from a supply and to form folded and sewn hems 
at the cut edges of the segment, with one of the hems being of a large 
size suitable for use as the hem at the head of a bed sheet. 
Another object of this invention is to provide a bed sheet production 
system which rapidly and accurately cuts segments of sheet material from a 
supply and accurately forms the head and foot hems in the bed sheet. 
Another object of this invention is to provide a hem expander attachment 
for a sheet production system, which accurately forms the large hem in the 
head of a bed sheet or a large hem in other sheet products. 
Another object of this invention is to provide a hem expander attachment 
for a sheet production system wherein a fold is made in the edge portion 
of the sheet material, and the fold is subsequently expanded. 
Other objects, features and advantages of the present invention will become 
apparent upon reading the following specification, when taken in 
conjunction with the accompanying drawings.

DETAILED DESCRIPTION 
Referring now in more detail to the drawings, wherein like numerals 
indicate like parts throughout the several views, FIG. 1 schematically 
illustrates the sheet production system 20, wherein sheet material 21 is 
taken from a supply such as from reel 22 and fed in an upward direction 24 
by a driven feed roller 25 at an inspection station, where a worker 
inspects the sheet material for flaws, etc. The flaws are marked with a 
liquid so that the flaws can be detected at the cutting station and the 
cut segment which includes a flaw can be identified. A particular sheet 
inspection and marking system suitable for use in this invention is 
disclosed in U.S. Pat. No. 4,204,012. 
The sheet material moves beyond driven roll 25 and then through a 
serpentine path about upper stationary rolls 26 and lower movable rolls 
28. The lower movable rolls are mounted on lever 29, and the lever 29 
pivots about fulcrum 30. Thus, the upper and lower rolls 26 and 28 
function as an accumulator 31 for the sheet material, to accommodate an 
increasing or decreasing supply of the sheet material from the inspection 
station. 
The sheet material moves from the accumulator 31 into cutting station 32. A 
cutter 33 is movable across the sheet material to form cut segments 34. 
Slack 35 is formed in the sheet material at the cutting station 32 just 
prior to cutting the sheet material, so that the cut segments 34 have 
slack therein as they are moved parallel to their cut edges 36 and 38 
through hem expansion station 39, and to hemming station 40, and then to 
pleat folder 41 and spiral folder 42. 
The sewing machines and hemming attachments of the type used at hemming 
station 40 are illustrated in U.S. Pat. No. 3,906,878, and the pleat and 
spiral folders 41 and 42 are illustrated in U.S. Pat. No. 4,227,684. An 
improved needle lubrication system of the type disclosed in U.S. patent 
application Ser. No. 238,037, filed Feb. 25, 1981 is used with the sewing 
machines in hemming station 40 in order to increase the speed of operation 
of the sheet production system. If it is desired to place labels in the 
finished product, a label dispenser of the type disclosed in U.S. Pat. No. 
4,157,692 can be utilized at the hemming station 40. 
As illustrated in FIG. 2, the cutting station 32, the hem expansion station 
39 and hemming station 40 are all located in alignment with one another 
and utilize a single work table assembly 71. Work table assembly 71 is a 
split work table, with left and right halves 72 and 74 which define an 
open space 75 therebetween. Additionally, right and left halves 72 and 74 
of the work table assembly 71 include cutting station segments 72a and 74a 
which are divided from the expansion and hemming segments 72b and 74b. The 
work table halves 72 and 74 are movable toward and away from each other to 
form the cut segments of sheet material in different lengths. This is 
accomplished with an electric motor and drive system (not illustrated). 
A conveyor tape assembly 76 is located in and along work table half 72 
while a similar conveyor tape assembly 78 is located in and along work 
table 74. Since each work table is broken at 79 and 80 to form a passage 
through the work table assembly, thus forming the work table assembly in 
sections, the conveyor tape assemblies 76 and 78 are also broken at 
passageways 79 and 80, with the conveyor tape assemblies being formed in 
sections 76a and 76b, and 78a and 78b. The conveyor tapes 76 and 78 are 
spaced from each other and are parallel to each other and extend at a 
right angle with respect to the direction of movement of the sheet 
material 21 as the sheet material enters the cutting station 32. 
CUTTING STATION 
Clamp assembly 81 (FIGS. 2 and 4-6) is located at the entrance 83 of 
cutting station 32. Clamp assembly 81 includes upper frame 82 and lower 
frame 84 which are vertically spaced apart and which permit the passage 
therebetween of sheet material 21. A rectilinear clamp bar 85 is mounted 
on the ends of a plurality of cylinder rods 86, and a plurality of 
pneumatic cylinders 88 are mounted in the upper frame 82. The clamp bar 85 
defines an elongated slot 89 in its bottom surface, and an elongated 
elastic tube 90 is mounted in the slot. Tube 90 protrudes from the bottom 
surface of bar 85 toward lower frame 84. Lower frame 84 has an upper 
horizontal surface 91 over which the sheet material 21 moves, and against 
which clamp bar 85 and its tube 90 bear. When clamp bar 85 is moved to its 
down position by its cylinders 88, the clamp bar holds the sheet material 
21 against the upper horizontal surface 91 of the lower frame 84, with the 
flexible tube 90 bearing against the sheet material 21 and against the 
upper horizontal surface 91. 
Lower frame 84 includes platform 92 that extends toward cutting station 32. 
Movable support means 94 rests on platform 92 and comprises a rectilinear 
beam of inverted U-shaped cross sectional shape including top surface 95 
and downward extending legs 96 and 98. A plurality of guide pins 97 extend 
through both legs 96 and 98 of movable support means 94 and through the 
upright wall portion 100 of lower frame 84. A coil compression spring 101 
surrounds that portion of each guide pin 99 between beam 94 and the 
upright wall portion 100 of lower frame 84, and the end heads 102 and 104 
of the guide pins 99 limit the movement of the beam 94 away from the 
upright wall portion 100. Thus, springs 101 bias the movable support means 
94 to the position illustrated in FIGS. 4 and 5. 
Gripping bar 105 comprises a channel-shaped beam 106 which includes top 
wall 108, side wall 109 and bottom wall 110. Rectangular support beam 111 
is mounted to the side wall 109 of channel beam 106 and supports the 
channel beam as illustrated. A plurality of pneumatic cylinders 112 are 
mounted to the top wall 108 of channel beam 106, and clamp bar 114 is 
supported by the cylinder rods 115 of cylinders 112. The clamp bar 114 is 
rectilinear and includes a rectilinear slot 116 in this lower surface, and 
an elongated elastic tube 118 fits in the slot. The arrangement is such 
that the clamp bar 114 and its tube 118, functioning as an upper clamp 
member, are moved toward and away from the bottom wall 110, which 
functions as a lower clamp member, whereby the assembly functions as a 
gripping means. 
As illustrated in FIG. 2, gripping bar 85 is mounted at its ends on 
trolleys 119 and 120, with each trolley being supported by its wheels 121 
on a track 122. A continuous chain drive 124 comprising chain 125, end 
sprockets 126 and 128 and air motor 129 function to move each trolley 119 
and 120 along their tracks 122. Trolley 119 moves adjacent the end of work 
table sections 72a and 74a while trolley 120 moves through the passageways 
79 and 80 between the work table sections 72a, 72a, and 74a and 74b. Thus, 
gripping bar 85 can be moved back and forth across cutting station 32 from 
the entrance thereof 83 to the other side thereof, 87. It will be noted 
that the clamp assembly 105 is long enough so that it extends beyond the 
trolley 120 and beyond the passages 79 and 80 formed in the work table 
assembly. 
As illustrated in FIG. 4, when gripping means 105 moves from its home 
position 88 across the cutting station 32 to the entrance 83 of the 
cutting station, it moves into abutment with the movable support means 94, 
with the lower clamp member 110 abutting the leg 96 of the movable support 
means 94. This causes the movable support means to move against the bias 
of its springs 101, so that the lower clamp member 110 moves in beneath 
the leading edge portion 21c of the sheet material 21. When the gripping 
bar 105 is in this position the upper clamp member 114 is moved down by 
its pneumatic cylinders 112 so that the leading edge portion 21c of the 
sheet material is gripped between the upper clamp member 114 and the lower 
clamp member 110. When the gripping bar then begins its movement from the 
entrance 83 back to its home position 88, it pulls the sheet material 21 
with it. In the meantime, clamp assembly 81 opens so as to allow the sheet 
material 21 to pay out and move with clamp assembly 105. 
As illustrated in FIG. 2, the framework of the work table assembly 71 
includes parallel support beams 134 and 135 which extend from cutting 
station 32 through hem expansion station 39 to hemming station 40. The 
parallel support beams 134 and 135 are supported over work tables 72 and 
74, and conveyor tape clamp bars 136 and 138 are supported from the 
support beams 134 and 135. Pneumatic cylinders 139 are spaced along 
support beam 134, and the cylinder rods 140 are connected to the support 
clamp bar 136, while pneumatic cylinders 141 are spaced along support 
beams 135 and their rods 142 are connected to and support conveyor tape 
clamp bar 138. The clamp bars 136 and 138 are positioned over the conveyor 
tapes 76 and 78 and are movable by their cylinders 139 and 141 down toward 
and abutment with the conveyor tapes. Thus, when sheet material 21 is 
extended across the cutting section 32 by gripping bar 105, the clamp bars 
136 and 138 are movable down into engagement with the sheet material to 
urge the sheet material into frictional contact with the conveyor tapes, 
so that when the conveyor tapes begin their movement, the sheet material 
will be moved with the conveyor tapes. 
Clamp bars 136 and 138 are broken into sections 136a and 136b, and 138a and 
138b, with the sections 136a and 138a extending over the passages 79 and 
80 between the segmented work table assembly, so that the end portions of 
the clamp bars 136a and 138a span the passageways 79 and 80. The sections 
116b and 138b are aligned with the sections 136a and 138a. 
Slack bar assembly 144 is mounted on support beam 135 and includes 
rectilinear slack bar 145 that extends parallel to conveyor tapes 76 and 
78 and which is located in the central open space 75 between the halves of 
the work table assembly, and L-shaped support legs 146 and 148, and rear 
connector bar 149. Clevises 150 and 151 pivotally connect the L-shaped 
support legs 146 and 148 to support beam 135. Pneumatic cylinders 152 and 
153 are mounted at the ends of rear connector bar 149 and function to 
pivot the slack bar assembly 144 about support beam 135, so that its slack 
bar 145 moves down into the plane of the sheet stretched across the 
central open space 75 (FIG. 5). 
As illustrated in FIGS. 2, 3 and 6, cutter 33 comprises a rectilinear guide 
beam 154 which extends across the entrance 83 of the cutting station 32 at 
the movable support means 94. A carriage 155 is mounted on cutter guide 
beam 154 and includes upper and lower brackets 156 and 158 mounted about 
the upper and lower surfaces of guide beam 154, and U-shaped housing 159 
having its upper and lower legs 160 and 161 mounted to brackets 156 and 
158. Cutter disc 162 is mounted, by means of bearing 164, in the side wall 
165 of U-shaped housing 159, with the axis of rotation of the cutter 
extending in a horizontal plane and with disc 162 extending in a vertical 
plane. A drive pulley 166 is connected to the disc drive shaft 168, and 
drive band 169 extends about pulley 166. A pair of idler pulleys 170 and 
171 direct the guide band 169 around approximately 180.degree. of the 
drive pulley 166, causing the drive band to frictionally engage and rotate 
drive pulley 166. Reversible electric motor 172 is mounted at the end of 
cutter guide beam 154, and its driven pulley 174 has drive band 169 
wrapped therearound. The band is also wrapped around idler pulley 175 
(FIG. 2) at the other end of the cutter guide beam 154. Thus, when 
electric motor 172 is energized, the movement of band 169 along its length 
causes disc 162 to rotate. 
Carriage conveyor belt 176 is mounted at its ends about pulleys 178 and 
179, and the pulleys 178 and 179 are mounted to the ends of cutter guide 
beam 154 by means of support straps 180. Reversible air motor 181 has its 
output shaft connected to pulley 179 and is arranged to drive carriage 
conveyor belt 176. Carriage conveyor belt 176 is connected to the top 
surface of carriage 155, so that movement of the carriage conveyor belts 
causes carriage 155 to traverse cutter guide means 154 and move cutting 
disc 162 across the sheet material. 
As is illustrated in FIG. 2, the second pair of conveyor tape assemblies 
182 and 184 are located in the hem expansion section 39 of the assembly, 
with the conveyor tape assemblies 182 and 184 being located parallel to 
and outside the conveyor tapes 76b and 78b. Conveyor tape clamp bars 185 
and 186 are located over conveyor tapes 182 and 184, with the pneumatic 
cylinders 188 and their rods 189 supporting clamp bar 185 and with the 
pneumatic cylinders 190 and their rods 191 supporting clamp bar 186. The 
clamp bars 185 and 186 are supported directly over conveyor tapes 182 and 
184 and are movable down toward and up away from engagement with the 
conveyor tapes and the sheet material carried thereon. 
As illustrated in FIG. 5, the conveyor tape clamp bars, such as clamp bars 
136 and 138, each include a rectilinear bar 104, a plurality of vertical 
holes formed vertically through the bar (not shown), and pins 205 
extending downwardly through the holes of the bar, with the heads 206 of 
the pins resting on the upper surface of the bar 204, and with the stems 
208 extending down beneath the bars 204. A slide or foot 209 is mounted on 
the bottom of pins 208, and a coil compression spring 210 surrounds each 
pin 208 beneath bar 204, and biases the foot downwardly away from the bar 
204. The conveyor tape clamp bars 136 and 138 are moved to their up 
positions by their cylinders 139 and 141 when gripping means 105 moves as 
indicated by arrow 211 away from the entrance 83 of the cutting station 32 
to its home position 87. After the gripping member has reached its home 
position 87, the clamp bars 136 and 138 move down toward engagement with 
the sheet material 21, over conveyor tapes 76 and 78. Cutter 33 is then 
energized, by air motor 181 moving carriage conveyor belt 176, causing the 
carriage 155 and disc cutter to move along the length of cutter guide beam 
154. In the meantime, electric motor 172 is energized to move its drive 
band 169 about drive pulley 166 of disc cutter 162, causing disc cutter 
162 to rotate. Thus, the sheet material will be cut by cutter 33 when 
gripping means 105, clamp bars 136 and 138 and clamp assembly have all 
engaged the sheet material 21, thereby holding the sheet material in a 
stable condition. 
After the cutter has completed the cut across the sheet material to form 
the cut segment 34, gripping means 105 release the sheet material 21 and 
the conveyor tapes 76 and 78 begin their movements, to move the cut 
segments 34 in a direction parallel to the cut ends of the segment from 
the cutting station 32 to the hem expansion station 39. 
HEM FORMING AND EXPANSION ATTACHMENT 
Conveyor tapes 76a and 76b (FIGS. 2, 5 and 6) move the cut segment 34 of 
sheet material from the cutting station 32 on into the hem expansion 
station 39. Outside conveyor tapes 221 and 222 move up into supporting 
relationship from the work table (FIGS. 7 and 13) to support the cut edge 
portions of the cut segment as they enter folders 224 and 225. 
As illustrated in FIG. 13, each folder includes a fold finger 226 that is 
supported in parallel, spaced relationship with respect to the work 
surface of the work table by support bracket 228, and includes an edge 229 
that extends approximately parallel to the cut edge 36 of the cut segment 
34 of sheet material, and an angled edge 230. Stationary edge folder 231 
is attached to the work surface and extends upwardly and curves about 
edges 229 and 230, and generally conforms to the shapes and angles of the 
edges 229 and 230. The stationary edge folder functions like a plow in 
that it lifts and turns over the cut edge portion 220 of each segment 34, 
so that the cut edge portion is folded over and on top of fold finger 226. 
The shape of edge folder 231 causes the material to be progressively moved 
onto the fold finger 226. 
As illustrated in FIG. 13, folding band 232 moves upwardly from its sheave 
234 through an opening in the work surface and moves into the edge folder 
231. The edge folder 231 includes a slot 235 into which the band initially 
moves, and the band 232 is guided over the edge 229 of the fold finger 226 
and extends at an angle inwardly of the angled edge 230 of the fold 
finger. Pulley 237 is located at the end of fold finger 226 and takes up 
folding band 232. Guide bracket 239 is located immediately in front of the 
sheave of pulley 237 that receives folding band 232, assuring that the 
band tracks directly toward the groove of the pulley 238. On its return 
flight, folding bad 232 is guided over fold finger 226 by sheave 240, then 
moves downwardly through an opening in the work surface, about another 
guide pulley (not shown), back to sheave 234. The guide pulley below the 
work surface is driven to impart movement to the folding band. The 
arrangement of folding back 232, fold finger 226 and outer belt 221 causes 
the cut edge portion 220 of the segment of sheet material to be 
progressively and positively folded over into overlying relationship with 
respect to the body portion of the segment of sheet material. 
As illustrated in FIGS. 13 and 14, fold platform 241 is also supported in 
spaced, parallel relationship with respect to the work surface 72b, by 
means of vertically extending support plate 242 connected at its lower 
edge to an edge of the fold platform 241, and by L-shaped support brackets 
244 attached to the upper portion of the vertical support plate 242 at 
spaced intervals along its length, and to work table 72b. Fold platform 
241 includes a rectilinear folding edge 245 that extends the entire length 
of hem expansion section 39, and fold finger 226 abuts the entrance end of 
fold platform 241, so that the angled edge 230 of fold finger 226 merges 
with the rectilinear edge 245 of fold platform 241. Thus, the cut edge 
portion 220 of the segment of sheet material 34 moves off fold finger 226 
onto fold platform 241. 
As illustrated in FIG. 13, platform belt 246 extends about pulley 238, and 
pulley 238 moves the platform belt down into engagement with the cut and 
folded over edge portion 220 of the sheet material as the cut edge portion 
moves on the upper surface of fold platform 241. Platform belt clamp 248 
is positioned over fold platform 241 and is located on top of the lower 
flight of platform belt 246. A plurality of support rods 249 are mounted 
to vertical support plate 242 and extend horizontally between the upper 
and lower flights of platform belt 246, outwardly over the platform belt 
clamp 248. Each support rod 249 is rotatably supported in its mount 250, 
and a set screw 251 extends through the mount 250 and holds the support 
rod 249 in place. The distal end of each support rod 249 is bifurcated, 
and a leaf spring 252 extends through the slot of the bifurcated distal 
end. Each leaf spring is also rigidly connected at one of its ends to the 
upper surface of platform belt clamp 248. Thus, the platform belt clamp is 
supported at spaced intervals along its length by the leaf springs 252 and 
support rods 249 and their mounts 250 from vertical support plate 242. 
When more or less downward force is to be applied by the platform belt 
clamp 248 against the platform belt 246, the set screws 251 can be 
loosened and the support rods 249 turned to change the force applied to 
the leaf springs 252. Thus, the platform belt 246 exerts a moving clamp 
action to the cut edge portion 220 of the cut segment of sheet material 34 
as the cut segment moves along fold platform 241, thus holding the cut 
edge portion from movement in a direction across its cut edge as the cut 
edge portion moves along the fold platform 241. Platform belt 246 is 
driven at the same linear speed as band belt 76 as the cut segment of 
sheet material moves into the hem expansion section 39, thus assuring that 
no wrinkles will be formed in the sheet material. 
As illustrated in FIGS. 10-12 and 14, a plurality of slots 255 are formed 
in fold platform 241 at spaced intervals along the length of the fold 
platform. The slots 255 are elongated and are aligned with one another 
along the length of fold platform 241. Slots 255 are positioned between 
vertical support plate 242 and platform belt 246 and its clamp 248. An 
elongated roller assembly 256 is located beneath the surface of work table 
72b and includes an axle 258 extending parallel to slots 255, and a 
plurality of bands 259 are mounted on axle 258 at spaced intervals along 
the length of the axle. The bands 259 are located beneath the slots 255 in 
fold platform 241. The bands 259 are also located in slots 260 formed in 
work table 72b, with the slots 260 being positioned beneath the slots 255 
in fold platform 241. 
A plurality of expansion clamps 262 are suspended above fold platform 241 
over slots 255 in the fold platform. Each expansion clamp 262 is L-shaped 
in cross section and includes horizontal leg 264 and vertical leg 265. 
Each expansion clamp 262 is of a length and width slightly less than the 
length and width of the slot 255 in fold platform 241. Each expansion 
clamp 262 is supported by cylinders 266 and their rods 268, with the 
cylinder rods being attached to the vertical leg 265 of a clamp 262. Each 
cylinder 266 is mounted by means of a bracket 269 to vertical support 
plate 242, and the cylinders 256 include an internal coil compression 
spring (not shown) that holds its cylinder rod 268 in a retracted, up 
position. Controlled air pressure communicates with the upper end of each 
of the cylinders 266 through conduits 270. Thus, cylinders 266 function to 
reciprocate expansion clamps 262 between a position where the expansion 
clamps 262 are retracted above the slots 255 of fold platform 241 (FIGS. 
10, 12 and 14) and to a position where the expansion clamps are moved 
downwardly through the slots 255 in fold platform 241 and bear against the 
upper surfaces of elongated roller assembly 256 (FIG. 11). 
As illustrated in FIG. 11, elongated roller assembly 256 includes a drive 
sprocket 271 mounted on its axle 258 and a rack 272 engages the teeth of 
sprocket 271. Rack 272 is reciprocated by cylinder 274 so as to drive 
elongated roller assembly 256. The angle through which roller assembly 256 
rotates is adjustable and is controlled by a positioning screw 275 in the 
end of cylinder 274. 
As illustrated in FIGS. 11, 12 and 14, a plurality of air nozzles 276 are 
mounted on expansion clamps 262, as by extending each nozzle 276 through 
the vertical leg 265 of the expansion clamps, so that the nozzles 276 are 
directed approximately parallel to the horizontal legs 264 of the 
expansion clamps. Flexible conduits 278 connected each nozzle 276 to a 
source of air pressure. 
When the cut segment of sheet material 34 has been moved by conveyor tapes 
76b along the work table and by platform belt 246 along fold platform 241 
a distance sufficient to move the entire cut segment of sheet material 
entirely into fold expansion section 39, as determined by a photocell (not 
shown) in the path of the sheet material, the movements of conveyor tape 
76b on the work table and of the platform belt 246 on fold platform 241 
momentarily terminate (FIG. 10). Then cylinders 266 move expansion clamps 
262 in a downward direction through slots 255 in fold platform 241 until 
the horizontal legs 264 of the expansion clamps have urged the body 
portion of the segment of sheet material into engagement with roller 
assembly 256 (FIG. 11). Immediately thereafter conveyor tape clamp 136b is 
raised away from conveyor tape 76b on work table 72b and roller assembly 
256 is rotated by its sprocket and rack 271, 272 (FIG. 11), moving its 
upper surface toward the fold in the sheet material. The raising of 
conveyor tape clamp 136b frees the body portion of the sheet material, 
while the rotation of the roller assembly 256 provides a moving surface 
against which the expansion clamp 262 has clamped the body portion of the 
sheet material. Thus, the body portion of the segment 34 of sheet material 
is pulled toward the fold in the sheet material. In the meantime, air is 
moved through conduits 278 leading to nozzles 276 carried by expansion 
clamps 262. This provides a flow of air directed beneath the fold platform 
241 (FIG. 11), into the hem. Thus, the portion of the sheet material 
pulled by the roller assembly 256 toward the fold in the sheet material 
will be expanded by means of air pressure, resulting in an expansion of 
the hem previously formed by folder 224. 
After the fold in the sheet material has been expanded in the manner 
illustrated in FIG. 11, hemming clamps 185 and 186 are moved downwardly 
toward engagement with the body portion of the cut segment of sheet 
material 34, to clamp the sheet material against hemming belts 182 (FIG. 
12) and immediately thereafter the expansion clamps 262 are raised away 
from roller assembly 256, upwardly through the slots 255 in fold platform 
241. The now expanded fold 280 in the cut edge portion of the segment of 
sheet material and the body portion of the segment are moved by conveyor 
tape 182 and by platform belt 246 on toward hemming station 40. Platform 
belt 246 is now moved at the same linear velocity as hemming belt 182. 
HEMMING STATION 
As illustrated in FIGS. 15 and 16, the segment of sheet material 34 moves 
from the hem expansion secton 39 on into the hemming section 40, by the 
segment moving out from beneath platform belt 246. Platform belt 246 is 
taken up by pulley 281. Folding band 282 extends about pulley 283 which 
idles on the same shaft as pulley 281 and folding band 282 is moved down 
into engagement with the folded edge portion of the sheet material and 
continues the movement of the sheet material along fold platform 241. Fold 
platform 241 includes fold finger projection 284 that extends 
coextensively with the fold platform 241, and is formed by notch 285 in 
the fold platform. Overlapping fold finger 286 is supported by bracket 288 
from vertical support plate 242, and overlapping fold finger 286 projects 
into the notch 285 and extends beneath fold finger projecton 284. Folding 
band 282 moves through notch 285 and beneath overlapping fold finger 286 
and moves on through the sewing machine 296 to compound pulley 300. In the 
meantime, stabilizing belt 290 is applied to the fold in the sheet 
material by its put-down sheave 291, runs off the end of fold finger 
projection 284, and is taken up by compound pulley 300. The fold finger 
projection 284, overlapping fold finger 286 and folding band 282 function 
to form the second fold in the cut edge portion of the sheet material, 
tucking the raw edge of the sheet material beneath the large fold. Folding 
band 282 assures that the leading edge of an oncoming segment 34 of sheet 
material moves beneath overlapping fold finger 286, and overlapping fold 
finger 286 tucks the raw edge beneath fold finger projection 284. 
When the segment of sheet material 34 emerges from the final folder, the 
now folded cut edge portion of the segment of sheet material moves into 
hemmer 295. Hemmer 295 comprises sewing machine 296 and entrance and exit 
guide plates 304 and 318 positioned over guide belt 290 and folding band 
282. The guide plates each include downwardly facing slots such as slots 
305 and 306 of guide plates 304 which conform to the shape of the band and 
belt, so as to guide and stabilize the band and belt as they approach and 
move away from sewing machine 296. Leaf spring 308 holds entrance guide 
plate in its proper position and applies the proper tension thereto. Lower 
transport belt 309 moves upwardly through the work table from its pulley 
310 and opening 311 and moves out from beneath fold platform 241 and then 
moves into its opening 312 in the work table about pulley 314 beneath 
entrance guide plate 304. 
As illustrated in FIGS. 15 and 16, separator plate 301 is formed of thin 
sheet metal with smooth upper and lower surfaces and one end portion 
thereof 302 is attached in overlying relationship to the lower surface of 
fold platform 241. The flexible separator plate extends beyond the end of 
rigid fold platform 241 and continues the separation of the folded layers 
of the segment 34 of sheet material; however, stabilizing belt 290 and 
folding band 282 apply downward force against the layers of the folded 
over edge portion 220 of the segment 34, the separator plate 301, the 
unfolded body portion 223 of the segment 34, the lower transport belt 309 
and the surface 72b of the work table, so that the lower transport belt 
controls the movement of the unfolded body portion 223 of the segment 
adjacent the fold in the segment and the belt 290 controls the movement of 
the folded over edge portion 220. Thus, the sheet material is accurately 
and positively transported from fold platform 241 on through sewing 
machine 296. 
Sewing machine 296 is a single needle sewing machine, and its needle 315 is 
arranged to sew through its presser foot 316 and between band 282 and belt 
290, through the three layers of the hem formed in the sheet material. The 
exit guide plate 318 which is similar to entrance guide plate 304 also 
stabilizes and guides band 282 and belt 290 as they move away from sewing 
machine 296. When the trailing edge of the segment of sheet material moves 
beyond sewing machine 296, the force applied by exit guide plate 318 to 
band and belt 282 and 290 keeps the trailing edge of the now sewn segment 
of sheet material from being snatched away from the sewing machine, 
causing the trailing edge to be moved gradually away from the sewing 
machine until it has emerged from compound pulley 300. 
DRIVE SYSTEM 
As illustrated in FIG. 17, the drive system for the conveyor tapes in the 
cutting section comprises motor 325 which drives through sprockets 326 and 
328 and chain 329 to rotate drive shaft 330. The drive systems for each 
conveyor tape are similar and include drive sprockets 331 and 332 with 
their connecting chain 334, shaft 335, sprockets 336 and 338 and their 
connecting chain 339, and conveyor tape 76a and 78a. Shaft 335 also 
extends through conveyor tape 76a and 76b to gear 340 which is connected 
through gears 341 and 342 to shaft 344 which drives conveyor tape 76b and 
78b, sprockets 345 and 346 and their connecting chains 348. 
The hemmer drives are similar to each other and each includes a motor 349, 
drive pulleys 350 and 351 and their connecting belt 352, drive shaft 354, 
gear reducer 355, sprockets 356 and 358 and their connecting chain 359 and 
conveyor tape 182. 
Lower transport belt 309 which carries the lower surface of the segment 34 
of sheet material from the fold platform to the needle of the sewing 
machine is driven by shaft 360 acting through sprockets 361 and 362 and 
belt 363 to drive phase shifter 364, and phase shifter 364 drives driven 
pulley 310 of transport belt 309. Air motor 365 controls phase shifter 364 
through its sprockets 366 and 367 and control chain 368. Valves 369 and 
370 control air motor 365, to cause an increase or decrease from the 
output shaft of phase shifter 364, causing lower transport belt 309 
momentarily to move faster than or slower than hemming belt 182, hemming 
guide band 301 and hemming stabilizing belt 302, to shift the lower 
transport belt 309 ahead or behind the hemming belt 182, the hemming guide 
band 301 and the hemming stabilizing belt 302. Lower transport belt 309 
therefore momentarily speeds up or slows down the movement of the body 
portion of the sheet material with respect to the folded over hem portion, 
so that the leading and trailing edges of the body and hem portions are 
formed in overlying relationship. With this arrangement, the leading and 
trailing edges of the hems being formed by the sewing machines, such as 
sewing machine 296, can be controlled so that no "dog ear" or protruding 
portion of the hem is permitted to be formed by the sewing machine. 
CONTROL CIRCUIT 
As illustrated in FIGS. 18A and 18B, three circuits are used to control the 
system. The first circuit is a 24 volt DC circuit, the second circuit is a 
110 AC circuit and the third circuit is a 220 AC circuit. 
The 24 volt DC circuit comprises main conductors 371 and 372, with 
conductor 371 being the negative conductor and conductor 372 being the 
positive conductor. A plurality of switches appear in the circuit and are 
termed timing switches. These switches are opened and closed by cams 
mounted on a rotatable cam shaft (not shown), with the cam shaft being 
driven by a timing motor. 
Main conductor 371 is connected to conductor 373 (FIG. 18B), which includes 
first stop switch 374, first start switch 375, accumulator switch 376 and 
the coil of first control relay CR1. Also connected in parallel with start 
switch 375 is second start switch 378 and the second contact CR1-2 of the 
control relay CR1. Thus, the second contact CR1-2 forms a holding circuit 
through the coil of the control relay. 
The coil of control relay CR1 in conductor 373 also closes the contact 
CR1-1 into 110 AC circuit (FIG. 18A), making a circuit from main conductor 
379, through conductors 380, 381, timing motor TM and main conductor 382. 
When timing motor TM begins its operation, it immediately closes timing 
switch TS1, making a circuit from main conductor 379 through conductor 
384, timing switch TS1, conductor 381, timing motor TM to main conductor 
382. This causes timing motor TM to continue its operation. When 
considering this function in connection with FIG. 18, it will be seen that 
switches TS1 and TS2 are first to close and last to open. Timing switch 
TS2 makes a circuit from main conductor 371 through conductor 385 and then 
through main conductor 386. Thus, timing switch TS2 functions to energize 
a common conductor 386 to which most of the DC circuits are made. 
Timing switch TS3 is in a circuit from common line 386 through conductor 
388 through manual switch 389, to pilot valve V3 which causes air motor 
129 to move the gripping bar 105 from its home position to the entrance 
position of the cutting station 32. In addition, in order to cushion the 
impact of the gripping bar 105 as it moves into the entrance 83 of the 
cutting station, valve V is energized parallel with pilot valve V3 through 
conductor 290 to charge a plurality of dash pots (not shown) which engage 
the oncoming gripping bar. 
After gripping member 105 has reached the entrance of the cutting station 
32, the cam system closes timer switch TS4 which makes a circuit from 
common line 386 through conductor 391, manual switch 392, and pilot valve 
V5 to main conductor 371. This causes the gripping bar to move its upper 
clamp member down against the lower clamp member 110 and to grip the 
leading edge portion 21c of the sheet material 21. 
After the gripping bar is in gripping relationship with the leading edge 
portion of the sheet material, the clamp assembly 81 is moved up. This is 
accomplished by a cam on the cam shaft closing timer switch TS5 which 
makes a circuit from common 386 through conduct 394, through manual switch 
395, through pilot valve V8 to main conductor 372. 
As soon as the clamp assembly is up to release the leading edge portion of 
the sheet material, the gripping bar is moved from the entrance position 
at the cutting station back to its home position to pull the sheet on into 
the cutting station 32. This is accomplished by closing timer switch TS6 
which makes a circuit from common 386 through conductor 394, manual switch 
395 through pilot valve V4 to main conductor 372. Also, a circuit is made 
through conductor 396 to dash pots (not shown) through valve V. The dash 
pots cushion the impact of the oncoming gripping bar 105. 
After the sheet material has been pulled into the cutting station by the 
gripping bar, the slack must be formed in the segment of sheet material by 
moving the slack bar 145 down into the sheet material. This is 
accomplished by a cam closing timer switch TS15 which makes a circuit from 
common 386 through conductor 428 to pilot valve V14 to main conductor 372. 
After the gripping member reaches its home position and slack has been 
formed in the sheet, the clamp assembly 81 is again moved into clamping 
relationship with the sheet material to hold the sheet material stable for 
the subsequent cutting step. This is accomplished by a cam closing timer 
switch TS7 which makes a circuit from common 386 through conductor 398, 
manual switch 399 and pilot valve V7 to main conductor 372. 
The first pair of conveyor tape bars 136 and 138 are moved down into 
engagement with the sheet material toward their respective conveyor tapes 
76 and 78 at the same time the clamp assembly is moved down to clamp the 
sheet material. This is accomplished by a cam closing the timer switch TS8 
which makes a circuit from common 386 through conductor 400, manual switch 
401, through pilot valve V9 to main conductor 372. Pilot valve V9 causes 
the pneumatic cylinders 139 and 141 of the clamp bars to move the clamp 
bars down into engagement with the sheet material. 
Now that the conveyor tape clamp bars, the clamp assembly and the gripping 
bars have all grasped the segment of sheet material extending through the 
cutting section 32, the disc cutter is actuated to cut across the sheet 
material. This is accomplished by a cam closing the timer switch TS9 which 
makes a circuit from common 386 through conductor 402, manual switch 404, 
and stepping switch 405 through either of conductors 406 or 408 to pilot 
valves V1 or V2 and to dash pot valves V which are in parallel with the 
pilot valves V1 and V2. Also, a parallel circuit is made through conductor 
409 through the coil of stepping relay CR3 and through the coil of the 
blade run relay CR5. The contacts 405 of stepping relay CR3 move 
alternately to change conductor 406 or 408, to move the knife in one 
direction and then in the other direction. Also, control relay CR2 in the 
24 volt circuit closes its contact CR2-1 in the 110 AC circuit, making a 
circuit from conductor 379 through conductor 410 to control relay CR4 to 
conductor 382. Control relay CR4 closes its contacts CR4-1 in the 220 AC 
circuit, or closes its contact CR4-2, causing the cutter disc motor 172 to 
reverse and begin operation. 
As the cutter disc is making its cut through the sheet material, the 
gripping bar 105 releases the leading edge of the sheet material. This is 
accomplished by closing timer switch TS10 which makes a circuit from 
common 386 through conductor 412, through manual switch 414 to pilot valve 
V6 and main conductor 372. 
After the cut in the sheet material has been completed and the gripping bar 
is opened, the first pair of conveyor tapes begin their movements to move 
the sheet material in a direction extending along the cut edges thereof to 
the transverse station. This is accomplished by closing timer switch TS11 
which makes a circuit from common 386 through conductor 415, manual switch 
416, through a photocell circuit 418, to pilot valve V13 to main conductor 
372. Pilot valve V13 actuates motor 325 and motor 325 continues to run 
until the photocell P in photocell circuit 418 sees the oncoming edge of 
the sheet material, whereupon the circuit to pilot valve V13 is opened, 
thereby causing the sheet to stop. 
When the cut segment of sheet material is moving from the cutting station 
32 to the transfer station 39, the second conveyor tape clamp bars 136 and 
138 must be raised momentarily in order to avoid retarding the movement of 
the oncoming edge of the cut segment of sheet material. This is 
accomplished by closing timer switch TS12 which makes a circuit from 
common 386 through conduct 420, manual switch 421 to pilot valve V12 to 
main conductor 372. Immediately thereafter, the conveyor tape clamp bars 
136 and 138 must be lowered again. This is accomplished by closing timer 
switch TS13 which makes a circuit from common 386 through conductor 422, 
manual switch 424 through pilot valve V11 to main conductor 372. 
After the sheet material has left the cutting station 31, the conveyor tape 
clamp bars 136a and 138a must be raised out of the way of the gripping 
member 105 so that the gripping bar can move back from its home position 
to the entrance position of the cutting station 32. This is accomplished 
by closing timer switch TS14 which makes a circuit from common 386 through 
conductor 425 through manual switch 426 through pilot valve V10 to main 
conductor 372. 
When a flaw appears in the sheet material the cut segment in which the flaw 
appeared is to be marked to identify that segment as having a flaw. The 
sheet inspection and marking system of the type disclosed in U.S. Pat. No. 
4,204,012 is used to make the mark on the segment. In order to detect that 
the last portion of the segment of sheet material to be cut is moving into 
the cutting station, timer switch TS16 is closed and makes a circuit to 
the marking system (not shown). 
The various manual switches identified throughout the circuit of FIGS. 18A 
and 18B permit the operator to temporarily close a circuit to the various 
functional elements of the system. For example, when it is desired to 
raise or lower the clamp assembly 81, the manual switch 399 or 395 can be 
moved from its normally closed position with its conductor 398 or 394 to a 
parallel conductor 399a or 395a to make a circuit to main conductor 371. 
The timing of the movements that are controlled by the circuitry 
illustrated in FIGS. 18A and 18B are illustrated graphically in FIG. 18. 
As illustrated in FIG. 20, the phase shifting of lower transport belt 309 
(FIG. 15) is controlled by a circuit 430. Photocells 431 and 432 are 
positioned in alignment with the path of the segments 34 of sheet material 
moving through the sewing machines 296. Photocell 431 in the upper portion 
of the circuitry detects the trailing edge of a segment passing to the 
sewing machine while photocell 432 in the lower portion of the figure 
detects the oncoming edge of the segment. The upper and lower portions of 
the control circuit of FIG. 19 are substantially the same, in that each 
includes a common line 434, conductor 435 leading from common to the 
photocell 431 or 432, an on/off switch 436, resistor 438 and transistor 
439. Transistor 439 emits a signal in response to a change in the signal 
from the photocell 431, and the signal is transmitted through diode 440 in 
parallel to capacitor 441 and resistor 442 to pulse relay 444. The 
variable resistance 445 is also connected to transistor 439 through 
resistance 446 and conductor 448. Thus, variable resistor 445 controls the 
duration of the pulse signal received from capacitor 441 to pulse relay 
444. 
When relay 444 is pulsed to its closed condition, a signal is received from 
conductor 449 through the closed switch 450 of relay 444, through 
conductor 451, resistance 452 and variable resistance 454, resistance 455 
to transistor 456. Capacitor 458 is connected in parallel through 
conductor 459 with respect to transistor 456. When transistor 456 is 
pulsed, it emits a signal to conductor 460, and in parallel through diode 
461 and air motor valve 369 (FIG. 16). Air motor valve 369 permits the 
passage of air under pressure through a conduit to air motor 365, causing 
a rotation of the corrector shaft 366, 367 of phase shifter 364. This 
causes a shift in the phase of the lower transport belt 309, causing a 
temporary slowdown of the belt. This causes the main body portion 223 of 
the sheet adjacent the folded over hem 220 to move slower as the trailing 
edge of the cut segment of sheet material moves through the sewing 
machine. Therefore, the folded over hem will not be permitted to hang out 
in its finally sewn together configuration and the selvages of the segment 
34 will be aligned. 
Photocell 431 which detects the oncoming trailing edge of the segment of 
sheet material is the type of photocell that detects light, while 
photocell 432 which detects the oncoming leading edge of the segment of 
sheet material is the type that detects dark. Thus, an extra transistor 
465 is placed in the lower portion of the circuit of FIG. 19 to invert the 
signal from photocell 432. The remaining portion of the lower circuit is 
substantially identical to the upper portion. The air motor valve 370 
therefore functions to control air motor 365, thus creating an input to 
the corrector shaft of the phase shifter 364, resulting in a change in 
speed of the lower transport belt 309 as it carries the lower main body 
portion of the segment of sheet material on into the sewing machine. It 
will be noted that there are two variable resistors 445 and 454 in both 
the upper and lower portions of the circuitry. Variable resistance 454 is 
used to fine tune the phase shifter while variable resistance 445 is used 
to multiply the effect of the signal received by air motor valve 369 or 
370. 
While this invention has been described in detail with particular reference 
to an embodiment which is specifically constructed to form bed sheets, 
wherein a hem expander is used to form the large hem at the head of a bed 
sheet, it will be understood that other sheet products can be fabricated 
with the disclosed system and hem expanders can be employed on both edges 
of the sheet material, if desired. Moreover, it will be understood that 
variations and modifications of the disclosed embodiment can be effected 
within the spirit and scope of the invention as described hereinbefore and 
as defined in the appended claims.