U.S. patent number 3,773,002 [Application Number 05/213,511] was granted by the patent office on 1973-11-20 for method and apparatus for folding and sewing hems.
Invention is credited to Perry E. Burton.
United States Patent |
3,773,002 |
Burton |
November 20, 1973 |
METHOD AND APPARATUS FOR FOLDING AND SEWING HEMS
Abstract
A method and apparatus for forming cloth lengths with folded
hems from a continuous supply of cloth wherein the supply of cloth
is intermittently fed along a first path to a cutting and transfer
station, a predetermined length of cloth is cut from the supply and
transferred to a second path extending approximately normal to the
first path, a cut end of the cloth length is double folded and
sewn, the cloth length is folded across its length so that its
other cut end is positioned on the same side as the hemmed end, and
the other cut end is double folded and sewn. The folded and hemmed
cloth lengths are folded again and stacked at the end of their
second path.
Inventors: |
Burton; Perry E. (Duluth,
GA) |
Family
ID: |
22795371 |
Appl.
No.: |
05/213,511 |
Filed: |
December 29, 1971 |
Current U.S.
Class: |
112/470.05;
112/130; 493/394; 493/423; 493/440; 112/475.06 |
Current CPC
Class: |
A41D
27/24 (20130101); D05B 33/02 (20130101); A41H
42/00 (20130101); D05B 41/00 (20130101); D05D
2207/04 (20130101); D05D 2305/12 (20130101); D05B
65/00 (20130101); D05D 2305/04 (20130101) |
Current International
Class: |
A41D
27/00 (20060101); A41D 27/24 (20060101); A41H
42/00 (20060101); D05B 33/00 (20060101); D05B
33/02 (20060101); D05B 65/00 (20060101); D05B
41/00 (20060101); D05b 033/00 () |
Field of
Search: |
;112/2,10,27,113,121.11,121.12,121.15,121.26,121.29,130,136,147,148,153,252,262
;270/66,93 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schroeder; Werner H.
Claims
I claim:
1. A method of fabricating lengths of cloth from a supply of cloth
comprising feeding cloth from a supply of cloth along a first path,
continually cutting predetermined lengths of cloth away from the
supply of cloth in the first path, moving the cut lengths of cloth
along a second path approximately normal to the first path without
changing the attitude of the cut lengths of cloth, folding over
twice and sewing one of the cut ends of each length of cloth as
each length of cloth moves along the second path, folding each
length of cloth across its length, folding over twice and sewing
the second cut end of each cut length of cloth, and wherein the
steps of folding over and sewing the cut ends of the lengths of
cloth comprise forming the chain of thread between the ends of
adjacent ones of the lengths of cloth, and advancing the folded and
sewn ends of each length of cloth toward the next adjacent length
of cloth along the second path a distance sufficient to create
slack in the chain of thread extending between the adjacent lengths
of cloth, urging the slack chains of thread downwardly with a
stream of air, and cutting the downwardly urged chains of
thread.
2. The method of claim 1 and wherein the steps of folding over and
sewing the cut ends of each length of cloth comprises
simultaneously retarding the movement of the cut edge of cloth as
it is first folded while advancing the cut end of the cloth ahead
of the remaining portion of the length of cloth as the cut end of
cloth is folded.
3. Apparatus for fabricating lengths of cloth from a continuous
supply of cloth comprising a transfer surface, feed means for
feeding the end of the continuous supply of cloth in a first
direction onto said transfer surface, sensing means for determining
when a predetermined length of cloth has been fed onto said
transfer surface, cutting means responsive to said sensing means
for cutting a length of cloth on said transfer surface from the
supply of cloth, conveyor means for receiving and moving the length
of cloth in a second direction generally normal to the first
direction, first edge folding and sewing means positioned adjacent
one side of said conveyor means for folding over and sewing one cut
edge of the cut length of cloth to form a closed hem along the
first edge as the cut length of cloth moves in the second
direction, folding means comprising a folding bar supported in a
generally stationary cantilever arrangement with its free end
extending above and in the direction of movement of said conveyor
means, and a wiper rod extending generally parallel to the
direction of movement of said conveyor means and movable from below
the path of the cloth on said conveyor means to above said folding
bar and then toward said one side of said conveyor means for
folding approximately one half the length of cloth about said
folding bar as the length of cloth continues to move in the second
direction, and second edge folding and sewing means positioned
adjacent said one side of said conveyor means for folding and
sewing the other cut edge of the length of cloth to form a closed
hem along the second edge as the length of cloth continues to move
in the second direction.
4. A method of forming a hem in a length of cloth or the like
comprising moving a length of cloth along a path approximately
parallel to an edge of the cloth, folding an edge portion of the
cloth over onto the body of the cloth with a surface moving
generally in the same direction as and at approximately the same
speed as the direction and speed of movement of the length of
cloth, holding the folded edge portion on the body of the cloth,
and unfolding the surface moving generally in the same direction as
the length of cloth from the length of cloth.
5. In a method of forming folded hems in the edge of sheets of
cloth or the like, the improvement comprising sequentially moving
sheets in a path approximately parallel to the edges to be hemmed,
passing an edge of each sheet through a stationary inwardly
converging fold forming guide to form a first fold at one edge of
each sheet, and engaging the first fold at the edge of each sheet
with a surface moving with and converging about the first fold to
form a second fold about the single fold.
6. The method of claim 5 and wherein the step of engaging the first
fold with a surface moving with and converging about the first fold
comprises moving a conveyor belt with the first fold and twisting
at least a portion of the conveyor belt into and over the first
fold.
7. The method of claim 5 and wherein the step of engaging the first
fold with a surface moving with and converging about the first fold
comprises engaging the first fold of each sheet with a surface
moving faster than the movement of the sheets along their path to
urge the first fold ahead of the remaining portion of its sheet as
the second fold is formed.
8. The method of claim 5 and further including the step of
disengaging the folded portion of the sheet with the surface moving
with the sheet, sewing through the folds, and forming back stitches
at the leading and trailing ends of the folds.
9. The method of claim 5 and further including the steps of
separating the moving surface and second fold in the sheets from
each other and sewing through the folds.
10. A method of forming hems in the opposite edges of cloth lengths
or the like comprising moving a series of cloth lengths along a
path with the opposite edges of the cloth lengths oriented
approximately parallel to the path, moving the portion of each
cloth length at its first edge faster along the path than the
remaining portion of the cloth length, passing the first edge of
each cloth length past an inwardly converging stationary fold
forming guide to form a first fold at the first edge of each cloth
length, engaging the first fold of each cloth length with a surface
moving with and about the first fold to form a second fold about
the first fold, sewing through the folds of each cloth length with
a back stitch at the leading and trailing ends of the folds,
forming a chain of thread between adjacent ones of the cloth
lengths, forming slack in the chains of thread, flowing air in a
downward direction about the slacked chains of thread to urge the
chains of thread lower than the cloth lengths and cutting the
chains of thread.
11. The method of claim 10 and further including the step of
folding the second edges of the cloth lengths across the cloth
lengths so that the second edges rest on the same side of the cloth
lengths as the first edges and repeating the steps of claim 14 with
respect to the second edges.
12. The method of claim 11 and further including stacking the cloth
lengths.
13. In apparatus for forming folded hems in the edges of lengths of
cloth or the like, the combination therewith of conveying means for
moving lengths of cloth in sequence along an approximately
horizontal path with the edges of the cloth to be hemmed oriented
parallel to the path, first folding means positioned at the edge of
the path and comprising an edge folding guide angled toward and
about the edge of the path for forming a first fold in the edge of
the length of cloth, and second folding means positioned at the
edge of the path and comprising a surface movable with and about
the first fold in the length of cloth for forming a second fold
about the first fold.
14. The apparatus of claim 13 and wherein said first folding means
is stationary.
15. The apparatus of claim 13 and wherein said second folding means
comprises a first stationay guide extending along the path, a
second stationary guide converging inwardly toward and about the
first stationary guide, and belt means movable along the path first
beneath said first guide and over said first guide and then
foldable with the second guide about the first guide.
16. Apparatus for forming folds at the edge of a sheet of material
or the like as the sheet is moved along a path approximately
parallel to its edge comprising a first stationary concave guide
surface converging into and along the path of the edge of the sheet
and curved about the path of the edge of the sheet in a
configuration for progressively forming a first fold in the sheet
at its edge as the sheet moves along its path, a first guide
surface extension extending along the path of the edge of the sheet
beyond said first guide surface and defining a helical surface
therein, a second stationary concave guide surface located inwardly
toward the middle portion of the path of the sheet from the first
guide member curved about the edge of the path of the sheet and
about the first guide member extension, and belt means including at
least a portion thereof movable with the sheet first beneath said
first guide member extension and then about the helical surface of
the first guide member extension until it emerges between said
first guide member extension and said second guide member in a
folded over configuration.
17. The method of claim 1 and wherein the steps of sewing the cut
ends of cloth comprises advancing the folded end of cloth toward a
sewing station, sewing the folded end of the length of cloth with a
sewing speed between the leading and trailing edges of the length
of cloth which is faster than the movement of the remaining portion
of the length of cloth along the second path, and back stitching
the folded end of the length of cloth at the leading and trailing
edges of the length of cloth.
18. A method of forming hems in edges of cloth lengths or the like
comprising moving a cloth length along a path with an edge of cloth
length oriented approximately parallel to the path, moving the edge
of the cloth length into a stationary fold forming guide converging
inwardly of the path to form a first fold in the cloth length at
the edge of the cloth length, engaging the first fold of the cloth
length with a surface moving with and about the first fold to form
a second fold about the first fold, separating the moving surface
and the second fold, and sewing through the fold of the cloth
length.
Description
BACKGROUND OF THE INVENTION
In the manufacture of cloth lengths, such as towels, diapers,
wiping rags, etc., the cloth lengths are usually manufactured by
cutting cloth in predetermined lengths from a continuous supply of
cloth and the cut ends of the cloth lengths are treated to prevent
the ends from raveling. The treatment at the cut ends of the cloth
lengths can comprise overedging, the application of an adhesive,
folding the ends over and forming stitches through the fold to
create a folded hem, or various other processes which form a hem
structure.
While various automatic machinery has been developed for feeding
out and cutting predetermined lengths of cloth, the prior devices
have been somewhat unsuccessful in that constant and close
attention is required by an operator in order to assure that the
cloth is properly aligned with a cutting apparatus, the cut lengths
of cloth are substantially equal in length, and the cuts are
properly formed at the ends of the lengths of cloth. In the past,
the cut cloth lengths were processed through sewing machines by
hand with the sewing machine operator guiding the cut ends of the
cloth lengths through a sewing machine to form the overedge
stitching or to form the folds and stitching through the folds.
While some automated machinery has been developed to relieve the
machine operators from the continuous close observation and control
of the sewing machines used for treating the cut ends of cloth
lengths, it usually has been necessary for the cut lengths of cloth
to be cut, accumulated in stacks, manually transferred to various
sewing stations, then handled by the sewing machine operators in
the end treating process, and restacked. The various manual steps
require the presence and attention of several workers and cause the
cloth lengths to be expensive to manufacture.
SUMMARY OF THE INVENTION
Briefly described, the present invention comprises a method and
apparatus for automatically forming hemmed cloth lengths wherein
cloth lengths are cut from a continuous supply of cloth, the cut
ends are folded over and sewn, and the cloth lengths are folded and
stacked for shipment, without requiring the manual handling of the
cloth lengths between the various steps of the process. The cloth
lengths are cut from a continuous sheet of cloth as the continuous
sheet is intermittently fed along a first path to a cutting
station, the cut lengths of cloth are then transferred to a second
path of movement which is generally normal to the first path of
movement of the continuous sheet of cloth, and the cut lengths of
cloth move in a path parallel to the cut ends of the cloth. The cut
ends are progressively folded, and the folds are sewn closed in a
continuous process. In order that only standard "right handed"
sewing machines be utilized to sew closed the folded ends of the
cloth lengths, the cloth lengths are folded across their lengths so
that the cut ends are placed on the same side of the cloth lengths,
and the folding and sewing steps are completed on one side of the
second path of movement of the cloth lengths.
Thus, it is an object of the present invention to provide a method
and apparatus for expediently and inexpensively forming cloth
lengths with folded hems from a continuous sheet of cloth.
Another object of this invention is to provide an inexpensive,
durable, versatile, and reliable apparatus for rapidly and
accurately cutting, folding and stitching the cut ends of cloth
lengths.
Another object of this invention is to provide various individual
methods and devices for performing the individual steps in a series
of steps required to cut cloth lengths from a continuous sheet of
cloth, fold over the cut ends of the cloth length, stitch closed
the folds, and stack the cloth lengths in a continuous process.
Other objects, features and advantages of the present invention,
will become apparent upon reading the following specification, when
taken in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic illustration of the method and apparatus for
forming cloth lengths with folded hems.
FIG. 2 is a detailed illustration of the feed roll and its related
elements.
FIG. 3 is a top view of the transfer table and transfer arm.
FIG. 4 is a perspective view of the edge folder.
FIG. 5 is a schematic illustration of the cloth lengths as one cut
end of each cloth length is folded and sewn closed.
FIG. 6 is an illustration of the crow's foot advancer, sewing head
and thread chain cutter.
FIG. 7 is a side elevational view of the stacker.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now in more detail to the drawing, in which like numerals
indicate like parts throughout the several views, FIG. 1
illustrates the apparatus for forming cloth lengths which is
broadly designated by the numeral 10 and which includes support
means 11 for supporting a roll or continuous supply 12 of sheet
meaterial such as woven cloth, terry cloth, or virtually any
textile fabric, plastic, paper or other sheet material. First feed
means 14 comprises a pair of rotatable rollers 15 and 16 which are
counter-rotatable and arranged to feed the free end of the supply
of sheet material therebetween. Rollers 15 and 16 are rotated by an
electric motor (not shown), and the on-off condition of the
electric motor is controlled by photoelectric cell 18 and the
appropriate electrical circuitry (not shown), so that when a free
supply of cloth 19 extends from feed means 14 in a downward
direction so as to block the light from light source 20 to
photoelectric cell 18, the feed rollers 15 and 16 terminate their
rotation and feeding of the cloth.
Feed table or platform 21 is positioned with its upper surface in
an approximately horizontal attitude, and the supply of cloth 12 is
fed in a single sheet over a horizontal guide bar 22 onto and
across the feed platform 21 toward feed roller 24. A resilient
sheet of material 25 is supported at one edge by its support bar 26
above feed platform 21 and slopes downwardly across the feed
platform 21 toward feed roller 24. Support bar 26 is angled so as
to bias the resilient sheet 25 down into engagement with the feed
platform 21 and the sheet of cloth on the platform, so that the
resilient sheet 25 functions as a drag means.
As is illustrated in FIG. 2, feed roller 24 comprises an inner feed
roll 28 which is rotatable in the direction indicated by arrow 29
by an electric motor and clutch (not shown), and the feed roll 28
is covered with a 3/8 inch sheet of flexible foamed polymeric
material 30 which is a resilient material that can be crushed and
will resume its original configuration. Such foamed polymeric
materials include latexes, polyurethanes, natural and synthetic
rubbers, and the like. More particularly, a suitable foamed
material is polyurethane foam obtainable by the reaction of
polyisocyanates with polyhydroxy compounds, such as polyethers and
polyesters. A particular foamed material is reticulated
polyurethane foam as disclosed in U.S. Pat. No. 3,171,820. The
material is cut into sheets of appropriate thickness, preferably
into sheets which are three-eighths inch thick, and has
approximately 30 pores per square inch. The texture of the sheet 30
is such that the opened cells tend to frictionally engage the
woven, knitted or other types of cloth or similar material such as
the supply 12 of sheet material, but the sheet does not tend to
penetrate, cling to or otherwise significantly frictionally engage
the hard, non-porous upper surface of feed platform 21. Thus, feed
roller 24 functions to feed the continuous supply of sheet material
across the feed platform without generating enough heat by its
sliding friction against the feed platform to damage the feed
platform or the roller.
The sheet material 12 can be virtually any material which can be
handled by the apparatus, and can include woven and other types of
material which has one edge more tightly woven than the opposite
edge or central body portion of the sheet material. The edge of
sheet material having a tightly woven edge or selvage usually is
slightly shorter than the remaining portion of the sheet and when
the sheet is fed by hard feed rollers, etc., the longer portions of
the sheet become wrinkled as the sheet passes through the rollers,
or the sheet tends to ride off the edge of the feed rollers.
An important feature of the arrangement of feed roller 24 is that
the material from which feed roller 24 is fabricated has the
ability to compensate for the different lengths of the sides of the
sheet material, such as woven cloth, etc. The crushing or
collapsing of the pore structure of the reticulated foam 30 of the
feed roller 24 as the foam engages the feed table 21 or the sheet
material being fed across the feed table causes the side of the
roller which feeds the tight selvage to allow a limited amount of
back slippage during the feeding process. This causes a positive
feed of the cloth along the length of the cloth without any
accumulation, folding or wrinkling of the cloth along its longer
portions by allowing the shorter edge of slip rearwardly with
respect to the longer edge across the feed area at the feed roller
24. Thus, the nonuniform structure of the cloth is compensated for
and no accumulation of cloth is allowed to build up at the feed
roller and cause the cloth to walk off the side of the feed roller
or allow the feed roller to feed wrinkles onto the transfer table
34.
The arrangement of the feed roller 24 together with the resilient
sheet 25 is such that these elements function as a feeding means to
feed the sheet material across and beyond feed platform 21, and the
cellular sheet or layer 30 about the feed roll 28 when engaging the
sheet material causes the sheet material to accelerate rapidly with
only controlled slippage between the feed roller 24 and the sheet
material 12, and when the feed roller rapidly decelerates, the
resilient sheet 24 functions as a drag means to assist in the
deceleration of the cloth, and the converging angle of the drag
means 25 with respect to the feed platform tends to keep any folds
or wrinkles from forming in the sheet material at the feed roller
25.
As is illustrated in FIG. 1, cutting blade 31 is located at the
edge of feed platform 21 and is hinged at its lower end at the feed
platform so as to be movable in an upward and downward direction to
cut the sheet material. Pneumatic ram 32 functions to oscillate
cutting blade 31.
Transfer table 34 functions as a transfer station to transfer the
cut length of material 35 from a first path of movement from the
support means 11 over the feed platform 21 to a second path of
movement which is approximately normal to the first path of
movement. Transfer table 34 comprises table 36 and a plurality of
conveyor tapes or belts 38a, 38b, 38c, and 38d which extend across
the top of table 36 and over conveyor rollers 39 and 40 and which
pass back beneath the table 36 and form a conveyor belt means.
While four conveyor tapes 38a-d are illustrated, it will be
understood that more or fewer conveyor tapes can be employed, or a
single wide conveyor belt can be employed, if desired. The exposed
surface of conveyor tape 38a has a relatively low coefficient of
friction with respect to the exposed surfaces of conveyor tapes
38b, 38c, and 38d. The texture of conveyor tape 38a is chosen so
that it forms a relatively slick moving or "live" smooth surface
with respect to the sheet material or length of cloth 35 passing
from feed platform 21 onto the transfer table 34. The conveyor
tapes 38b-d therefore form a first surface portion having a
relatively high coefficient of friction while tape 38a forms a
second surface portion having a relatively low coefficient of
friction.
Photoelectric cell 41 is positioned in the vicinity of transfer
table 34 and is arranged to detect the presence or absence of light
from the surface of the table, as by reading the light 42 from
below transfer tabel 41. Photoelectric cell 41 together with the
appropriate circuitry is arranged to control the rotation of feed
roller 24, the downward movement of cutting blade 31, and the
rotation of transfer table conveyor rollers 39 and 40. The
arrangement is such that when the photoelectric cell 41 sees light
from its light source 42, feed roller 24 rotates to feed the supply
of sheet material across feed platform 21, and conveyor rollers 39
and 40 function to move the conveyor tapes 38a-d across table 36.
Conveyor rollers 39 and 40 function to move the conveyor tapes
38a-d at a linear velocity which is faster than the linear velocity
of the sheet material onto transfer table 34, so that the convehor
tapes tend to stretch out the leading portion of the sheet material
away from feed roller 24; however, since the feed roller 24
positively grips the supply of sheet material 12 against the upper
surface of feed platform 21, the conveyor tapes 38a-d will tend to
move out from beneath the supply of sheet material unless the sheet
material is folded or wrinkled, whereupon the folds or wrinkles
will be stretched out away from feed roller 24 and removed from the
cloth. When the photoelectric cell detects darkness by the leading
edge of the cloth blocking the light from light source 42, feed
roller 24 will stop its rotation and cutting blade 31 will move
under the influence of its ram 32 in a downward direction to cut
away that portion of the sheet material extending from the cutting
blade over the transfer table, and the conveyor rollers 39 and 40
of the transfer table will decelerate at a rate slower than the
deceleration of feed roller 24. When the cutting blade 31 has moved
to its full down position where the sheet material has been cut,
its limit switch (not shown) will open and ram 32 will reverse to
lift the cutting blade 31 back up to its ready position. The slower
deceleration of the conveyor tapes compensates for any folds that
might be created in the cloth from any snap back of the cloth on
the transfer table which might result when the cloth is cut. As
long as the now cut length of material remains on transfer table 34
to block the light from light source 42 to photoelectric cell 41,
no further feeding or cutting of the sheet material will take
place.
Transfer arm 45 is located above transfer table 34, and its lower
surface comprises a layer of the cut foamed material 46 of the type
used on feed roller 24. Transfer arm 45 is normally maintained
above the conveyor tape 38a which has the slick exposed surface.
Pneumatic rams 48 and 49 control the movement of transfer arm 45,
with ram 48 functioning to move the transfer arm 45 down into
engagement with the portion of the cut length of material which
covers conveyor tape 38a, while ram 49 functions as a transfer ram
and urges transfer arm 45 off transfer table 34 and onto sewing
table 50. As is illustrated in FIG. 3, transfer ram 49 is angled so
that its motion off transfer table 34 is less than 90.degree. from
the first path of movement of the continuous supply of sheet
material, as indicated by arrow 13. The support for rams 48 and 49
is pivotally connected to table 36 by upright support bar 51, and
the angle which transfer ram 49 takes with respect to table 36 is
controlled by adjustable turn buckle 52.
Sewing table 59 comprises a table surface 54 disposed in an
approximately horizontal plane, and a plurality of conveyor tapes
55a, 55b, 55c, and 55d extend across the table and return back
beneath the table so as to move the lengths of material 35 in a
second path 56 which is approximately normal to the first path 13
and which is parallel to the cut ends of the lengths of cloth or
sheet material. Conveyor tape 55a is mounted on a roller of
slightly larger diameter so that the surface speed of conveyor tape
55a is faster than the surface speeds of the remaining conveyor
tapes. A plurality of stationary leaf springs 58 are mounted on a
support 59 extending above the sewing table, and the leaf springs
are urged down into engagement with the conveyor tapes 55a-d. The
leaf springs 58 are fabricated from a smooth material so that they
slide easily with respect to the conveyor tapes or the cut lengths
of material passing over the conveyor tapes. Thus, the leaf springs
function to urge the cut lengths of material passing along second
path 56 into engagement with the conveyor tapes, so that the higher
friction between the conveyor tapes and the cut lengths of cloth
functions to cause the lengths of cloth to move in unison with the
conveyor tapes across the sewing table. While only one set of
stationary leaf springs is illustrated, several sets are used along
the length of sewing table 50 as required to urge the cloth lengths
to move with the conveyor tapes. In addition, movable leaf springs
59 are supported in cantilever fashion by rotatable support bar 60,
and the movable leaf springs are pivoted by pneumatic ram 61 at the
end of bar 60 into and out of engagement with the cut lengths of
cloth passing with the conveyor tapes across the sewing table.
Photoelectric cell 62 is located above the table surface and is
arranged to detect the presence or absence of light emanating from
the table surface, as from light source 64 located beneath the
table surface. Photoelectric cell 62 together with the appropriate
circuitry functions to actuate transfer arm 45. More specifically,
when photoelectric cell 62 detects the presence of light, pneumatic
ram 48 of transfer arm 45 is actuated to urge the transfer arm
downwardly toward the smoother conveyor tabe 38a of transfer table
34 until it engages the cut length of cloth present on the transfer
table, transfer ram 49 is caused to distend and move transfer arm
45 from conveyor tape 38a and transfer table 34 toward sewing table
50 until the transfer arm limit switch (not shown) is engaged,
whereupon ram 48 retracts, and ram 49 retracts to return the
transfer arm to its elevated ready position. The movement of
transfer arm 45 is rectangular movement, first down, then across,
then up, then back. When the transfer arm limit switch is closed by
the transfer arm 45 having been moved to its furtherest position
over on sewing table 50, the limit switch functions to actuate
pneumatic ram 61 and pivot support bar 60 so that movable leaf
springs 59 move down into engagement with the cut length of cloth
and urge the cloth into engagement with the conveyor tapes 55a- d
of the sewing table, thus causing the cut length of cloth to move
in unison with the conveyor tapes across the sewing table. As the
cut lengths of material move in series with the conveyor tapes,
they pass beneath the stationary leaf springs 58 and are therefore
continuously urged into engagement with the conveyor tapes. When
the photoelectric cell 62 again detects light, pneumatic ram 61 is
reversed to lift the movable leaf springs 59 out of engagement with
the cut lengths of material and return the leaf springs to their
ready positions. Moreover, when the photoelectric cell 62 again
detects light, it begins its cycle again to transfer a cut length
of material from transfer table 34 from the first path 13 toward
the second path 56.
As the cut lengths of material 35 move along second path 56, the
first cut edges 63 and the second cut edge 64 are approximately
aligned with the direction of movement of the cut lengths of
material. The second cut edge 64 lis trimmed by a conventional edge
trimmer 65 so that if any imperfections are present in the cut edge
of the length of sheet material they will be remedied. The cloth
lengths 35 are then moved further along second path 56, and second
cut edge 64 passes through first edge folder 66.
First edge folder 66 comprises a first stationary concave guide
member 68 having a concave guide surface 69 which converges into
and along the path of the second cut edge 64 of the sheet material,
and is curved about and around the upper portion of the path of the
second edge so as to induce the edge of the cut length of material
35 to form a fold along the edge of the material. Presser foot 70
is positioned along the edge of the path of the cut sheet material
35 at a position displaced inwardly from the edge of the material.
Presser foot 70 extends into guide member 68 and presses the cut
sheet of material 35 into positive engagement with conveyor tape
55a as the first fold is being created along the edge of the sheet
of material.
First guide member extension 71 has a helical configuration and
extends beyond first guide member 68. Second guide member 72 is
positioned further down the path from first guide member 68 and is
located inwardly toward the middle portion of the path of the sheet
material from the first guide member, and is curved about the edge
of the path of the sheet and about the first guide member extension
71. Second guide member 72 is located inwardly of the normal path
of travel of the edge of conveyor tape 55a, and induces the
conveyor tape 55a to form a fold in its edge at 74. First guide
member extension 71 extends from first guide member 68 into second
guide member 72 and functions to guide the first fold formed in the
edge of sheet of material and the edge of the conveyor tape 55a
into second guide member 72, thus forming a fold in the conveyor
tape 55a and a second fold in the edge of the sheet material
35.
When the conveyor tape 55a emerges from second guide member 72, the
folded portion of the conveyor tape is allowed to unfold and
continue as a flat conveyor tape. Second pressure foot 75 is
positioned in alignment with second guide member 72 and reaches
into the fold of the conveyor tape as it unfolds from the second
guide member 72 to contact the double fold in the edge of the sheet
of material 35 to cause the double fold to be maintained in the
sheet material while the fold in the conveyor tape 55a is
straightened.
Conveyor tape 55a is moved at a greater velocity than the remaining
conveyor tapes 55b- d. As is illustrated in FIG. 5, the faster
movement of conveyor tape 55a causes the cut edge 64 of the cut
length of sheet material 35 to move ahead of the remaining portion
of the cut length of material. When the second cut edge 64 is
passed through first guide member 68, the friction between the cut
edge 64 and the stationary curved surface 69 of the first guide
member 68 casues the edge 64 to distort rearwardly of the leading
edge of the sheet material, as indicated in sheet 35b of FIG. 5.
Thus, the leading end 76 and trailing end 81 of the first fold 77
outside fold line 78 in the sheet material will be displaced at an
angle from the fold line 78 which is less than 90.degree. from the
fold line; however, the increased velocity of the conveyor tape 55a
forming the second fold and carrying the edge portion of the length
of material advances the second cut edge 64 ahead of the leading
end 79 of the sheet of material so that the portion of the leading
end 76 and trailing end 81 inside fold line 78 is distorted ahead
at an angle approximately equal to the angle made by the leading
and trailing ends outside the fold line 78, so that the ends of the
first fold 77 are approximately coextensive with the leading and
trailing ends of the sheet of material. Also, when the second fold
80 is completed about fold line 78b, the leading ends of the first
and second fold will be coextensive with the leading end 79 of the
sheet of material, and there will be no hem "hangout" at the
leading or trailing ends of the fold.
As is illustrated in FIGS. 1 and 6, crow's foot advancer 82 is
positioned above the path of travel of the second cut edge 64 of
the cut lengths of material, beyond edge folder 66. Crow's foot
advancer 82 comprises pneumatic ram 84, ramrod 85, stem 86 and
crow's foot 87. When the rod 85 of ram 84 is retracted, stem 86
abuts rest 88 and the end of the crow's foot 87 and is slightly
retracted above the path traveled by the double fold along the edge
of the cut sheet of material. When ram 84 distends its rod 85, the
end of crow's foot 87 will engage the double fold 80 and urge the
leading end 90 of the double fold into the needle of first sewing
machine 91. Ram 84 is regulated so that it urges its crow's foot 87
at a velocity approximately equal to the velocity of conveyor tape
55a, which is faster than the velocities of the reamining conveyor
tapes 55b- d. Thus, the distortion in the edge of the sheet
material is maintained until the leading end 90 of the double fold
80 reaches the presser foot of the sewing machine.
Photoelectric cell 92 is arranged to detect the presence or absence
of light from the surface of the sewing table 50, as from light
source 93 positioned below the table, so that the leading end of a
sheet of material passing along the sewing table will block the
light from the photoelectric cell. Photoelectric cell 92 and the
appropriate circuitry functions to control the operation of crow's
foot advancer ram 84 and the timing when the crow's foot 87 reaches
down into engagement with the leading end 90 of the double fold 80
in the sheets of material. When the ram 84 has fully distended its
rod 85, a limit switch (not shown) functions to reverse ram 84 and
retract the crow's foot.
Sewing machine 91 is a high speed machine arranged to operate
continuously and to form a chain of thread between the adjacent
ones of the sheets of material passing along the sewing table.
Sewing machine 91 is a reversible sewing machine of conventional
design, such as Pfaff, model 438-6/01-AS, manufactured in West
Germany, or the reversible machine manufactured by Union Special
Sewing Machine Company. Photoelectric cells 94 and 95 positioned
above sewing table 50 function to detect the presence or absence of
light from the surface of the sewing table, as from light source 96
positioned below the sewing table, so that when a sheet of material
is moving along the sewing table its leading and trailing edges
will be detected. Photoelectric cells 94 and 95 are arranged to
momentarily reverse sewing machine 91. For instance, photoelectric
cell 94 is arranged to momentarily reverse sewing machine 91 when
it detects the leading edge of a sheet of material 35 so that the
sewing machine functions to create a backstitch 98 at the leading
end 90 of the double fold or hem 80, and then continue with the
regular stitch 99 along the intermediate portion of the double
fold, while photoelectric cell 95 functions to reverse the sewing
machine 91 when the trailing end of the double fold is beneath the
sewing machine, so as to form a backstitch 100 at the trailing end
of the double fold. Since the edge of the sheet material having a
double fold hem therein is advanced ahead of the remaining portion
of the sheet material by means of the conveyor tape 55a of edge
folder 66 and then by crow's foot advancer 82, the sewing machine
91 can momentarily stop the advancement of the folded portion of
the sheet material to form the first backstitch 98 without unduly
distorting the sheet material. Sewing machine 91 is adjusted to
operate at a speed which is faster than the velocity of the sheet
material along sewing table 50, that is, the feeding and stitching
mechanism of the sewing machine advances the hem along path 56 at a
rate faster than the conveyor tapes 55b- d advance the remaining
portion of the sheet material, so that by the time the trailing end
81 of the double fold 80 of the sheet of material reaches the
sewing machine, the folded end portion of the sheet material is
again advanced ahead of the remaining portion of the sheet material
and the sewing machine can again be reversed to form double stitch
100 at the trailing end of a heam without unduly distorting the
flat sheet material.
As is illustrated in FIGS. 1 and 6, cutting means 102 is provided
in sewing table 50 and defines an opening 104 in the table surface
54, a slotted cutter head 105, a plurality of rotatable cutter
blades 106, an air suction means 108. The slotted head 105 is
formed so that the flat sheet material cannot enter the opening 104
and reach the rotating blades 106; however, the thread chain 109
extending between the adjacent ends of the sewn hem can be received
in the slot of the head 105, and the suction means 108 tends to
induce the thread chains to enter the slot. Moreover, since sewing
machine 91 operates to move the hem of the sheet material at a
faster velocity than the remaining portion of the sheet material,
the leading end of the hem will advance toward the trailing end of
the hem of the sheet material ahead of it to create slack in the
thread chain, so that the thread chain can reach the rotating
blades 106 through the slotted head 105 of the cutter 102. With
this arrangement, substantially all of the thread chain extending
between the adjacent hems is cut and removed from the vicinity of
the sheets of material.
As is illustrated in FIG. 1, fold bar 110 is supported from table
surface 54 and extends above and along the path 56 of the sheet
material in a cantilever arrangement. Fold bar 110 is adjustable so
that its folding edge 111 can be accurately positioned along path
56. The sheets of material 35 pass beneath fold bar 102. Wiper rod
112 extends parallel to path 56 and is mounted on a pair of chains
114. Chains 114 are endless chains and include upper flights 115
which extend laterally with respect to path 56 above table surface
54, and lower flights 11 which extend beneath the table surface. A
slot 118 is provided in the table surface so that wiper rod 112 can
travel in a closed continuous path and emerge up through slot 118
in the table surface, then move in a lateral direction above and
laterally across the table surface and fold bar 110, and then pass
with the lower flights of the chains back beneath the table
surface. Photoelectric cell 120 is positioned above the table
surface so as to detect the presence or absence of light emitted
from the table surface, as by light emanating from light source 121
beneath the table surface, so that the presence or absence of the
leading edge of a sheet 35 will be detected. Photoelectric cell 120
together with the appropriate circuitry controls the movement of
wiper rod 112, and when photoelectric cell 120 detects the absence
of light from the presence of sheet material passing between
photoelectric cell 120 and its light source 121, wiper rod 112 will
emerge through its slot 118 and then move upwardly and over fold
bar 110 and table surface 54 and wipe or fold over the first cut
edge 63 of the sheet material so that the first cut edge 63
overlaps or extends beyond the first hemmed edge of the sheet
material. When the wiper rod 112 moves along its return flight
beneath the sewing table, it engages its limit switch (not shown)
so that its movement is terminated until photoelectric cell 120
initiates its movement again.
Since the endless chain 114 which support wiper rod 112 completely
surround the folded sheet material, the sheet material is therefore
free to pass between the upper and lower chain flights and move
through and beyond the folding mechanism. The sheet material uses
the edge 111 of the fold bar 110 as a reference point, and the fold
in the sheet material is formed about the edge 111. When the sheet
material reaches the end of fold bar 110 it drops off the fold bar
and continues on its path 56 through chains 114. Wiper rod 112 can
be supported on chains 114 so that it rotates about its
longitudinal axis and therefore rolls about its axis as it wipes a
fold into the sheet material and therefore minimizes the frictional
engagement with the sheet material, or wiper rod 112 can be formed
as a bent rod, somewhat crescent or banana-shaped with the center
portion of the rod as it moves across and above the sewing table
leading the end portions, so that the middle portion of the end of
the sheet material being wiped or folded tends to lead the corners
during the wiping movement, and the corners will then come rest in
a flat, unwrinkled position. This reduces any tendency of the
corners from becoming wrinkled, folded or otherwise distorted in
the following function.
Once the sheet material has been folded by fold bar and wiper rod
112 as previously described, the first cut end 63 of the sheet
material is double folded and the double fold is sewn closed in a
manner similar to that previously described and illustrated in
FIGS. 4, 5 and 6. For instance, as illustrated in FIG. 1, a second
edge folder applies a double fold to the first cut edge at 125, a
second crow's foot advancer 126 advances the second double fold to
a second sewing machine 128, and a second thread chain cutter 129
cuts the thread chain between the adjacent hems.
When the hemmed and folded sheets 35 reach the end of sewing table
50, the sheets are folded again and stacked by stacker 130. As is
illustrated in FIG. 7, the sheets 35 are allowed to flow off the
end of the sewing table and in a downward direction until the
leading end of the sheets reaches the vicinity of photoelectric
cell 131 and blocks the light emanated from light source 132. At
this point, a tucking blade 134 is pivoted from beneath the table
surface of the sewing table and extended over and above the top
surface of a grate 135 of stacker 130. A stream of air from air
tube 136 assists the downward movement of the leading edge of the
sheet 35 between the sewing table 50 and stacker 130. Photoelectric
cell 131 together with the appropriate circuitry functions to
actuate stacker 130. Stacker 130 comprises a framework 138,
horizontal platform 139, collapsible grate 135, transfer arm 140,
and arm support levers 141 and 142. Collapsible grate 135 is formed
in two door sections hingedly supported on opposite sides so as to
function as a trap door in that it opens in its center portion in a
downward direction, as illustrated in the dashed line position of
FIG. 7. When photoelectric cell 131 detects the presence of the
leading end of a sheet 35, pneumatic ram 144 distends to move the
tucker blade 145 to its dashed line position and the tucker blade
forms a second fold in the sheet material and carries the second
folded portion of the sheet over onto the grate 135. Pneumatic ram
145 then distends to pivot support arm 141 in a downward direction
with respect to support arm 142, causing transfer arm 140 to move
downwardly into engagement with the fold created in the sheet 35
about tucker blade 134. Pneumatic ram 146 contracts to pivot
support arm 142 about its upper end, thus moving transfer arm 140
across grate 135 until support arm 145 reaches its broken line
position. When in this position, support arm 142 engages its limit
switch 148, whereupon pneumatic ram 149 opens grate 135 and allows
the now folded sheet 35 to drop from the gate 135 onto horizontal
platform 139. Also, pneumatic ram 145 lifts support arm 141 and
transfer arm 140 with respect to grate 135, while pneumatic ram 146
distends to return transfer arm 140 back to its start position.
When grate 135 has completely opened, its limit switch will
function to reverse pneumatic ram 149 to return the grate to its
closed position and to reverse ram 144 to return tucker blade 134
to its ready position.
If desired, tucker blade 134 can be deactuated, framework 138 of
stacker 130 can be moved closer to the sewing table so as to
eliminate the space between the end of the sewing table and the
stacker, and photoelectric cell 131 can be moved to detect the
leading end of the sheet material 35 as it first moves off the
surface of the sewing table and onto grate 135. This allows
transfer arm 140 to be energized as soon as the leading edge of the
sheet material moves onto the grate 135, so that the second fold
formed in the sheet 35 with the previous arrangement will be
eliminated.
While this invention has been described in detail with particular
reference to preferred embodiments thereof, it will be understood
that variations and modifications can be effected within the spirit
and scope of the invention as described hereinbefore and as defined
in the appended claims.
* * * * *