United States Patent 1 Burton METHOD AND APPARATUS FOR FOLDING AND SEWING HEMS  Inventor: Perry E. Burton, Box 655, Duluth,
 Filed: Dec. 29, 1971  Appl. No.: 213,511
 References Cited UNITED STATES PATENTS 3,640,235 2/1972 Burton 112/l2l.29 3,500,780 3/1970 Emus et a1. 112/121.29 3,582,663 6/1971 Troast, Jr. et a1... 112/130 X 3,459,142 8/1969 Berg 112/10 11 3,773,002 Nov. 20, 1973 3,463,482 8/1969 Baron et al. 270/93 Primary Examiner-Werner H. Schroeder Attorney-Harold D. Jones, Jr. et a1.
 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 s'o'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. I
18 Claims, 7 Drawing Figures PATENTED NOV P. 0 i975 SHEET 2 OF 4 FIG 4 PATENTED W20 i973 SHEET 3 BF 4 FIG 6..
- PMENIEUuuvzo 1975 37711002 sum u or 4 FIG 7 METHOD AND APPARATUS FOR FOLDING AND SEWING I-IEMS 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 crows 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 l5 and 16 are rotated by an electric motor (not shown), andthe 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 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 inelude 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 cocfficient 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 38ad 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 out 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 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 SSa-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. ln 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 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 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 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 SSa-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 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 55bd. 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 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, crows 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. Crows foot advancer 82 comprises pneumatic ram 84, ramrod 85, stem 86 and crows foot 87. When the rod 85 of ram 84 is retracted, stem 86 abuts rest 88 and the end of the crows 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 crows 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 SSb-d. Thus, the distortion in the edge of the sheet material is maintained until the leading end 90 of the double fold 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 crows foot advancer ram 84 and the timing when the crows foot 87 reaches down into engagement with the leading end 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 crows 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/Ol-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 crows foot advancer 82, the sewing machine 91 can momentarily stop the ad vancement 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 SSb-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 1 10 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 1 12 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,
edge 111. When the sheet material reaches the end of fold bar 1 10 it drops off the fold bar and continues on its path 56 through chains 1'14. Wiper rod 112 can be supported on chains 114 so that it rotates about its lon- 4 and the fold in the sheet material is formed about the V gitudinal 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 comers 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 crows 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 vicinityof 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 comprises a framework 138, horizontal platform 139, collapsible grate 135, transfer arm 140, and arm support levers 141 and 142. Collapsible grate 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 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 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.
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. [n 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 firstfold, 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 thecloth lengths and cutting the chains of thread.
11. The method of claim 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.
v 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 sec ond 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.