US3461825A

US3461825A - Sheet-handling apparatus

Info

Publication number: US3461825A
Application number: US674398A
Authority: US
Inventors: Roy J Brown
Original assignee: KOR IT CO Inc
Current assignee: KOR IT CO Inc
Priority date: 1967-10-11
Filing date: 1967-10-11
Publication date: 1969-08-19
Anticipated expiration: 1986-08-19

Description

. Aug. 19,1969 R. J. BROWN n we Y Filed Oct.' 11, 1967 FIGJ W) 50 I48 INVENTOR FIG.2 ROY J. BROWN ATTORNEYS Aug. 19, 1969 Filed Oct. 11. '19s? FIG.3

R. J. BROWN SHEET-HANDLING APPARATUS 6 Sheets-Sheet 2 mvlzuwn Rev J. BROWN ATTORNEYS 19, 1969 R. J. BROWN 3 SHEET-HANDLING APPARATUS 6 Sheets-Sheet 5 Filed Oct. 11, 1967 |0\ FIG.5

INVENTOR ROY J. BROWN Aug. 19, 1969 I J, BROWN 3,461,825

SHEET-HANDLING APPARATUS Filed Oct. 11, 1967 6 Sheets-Sheet 4 FIG.7

28 T f 4 a 0 FM) 3 12 a0 49 \IO FIG.8

INVENTOR ROY J. BROWN ATTORNEYS Filed Oct. .11. 19s? W 196,9 R. J. BROWN 3,461,825

I sarmwmmomm APPARATUS v 6 Sheets-Sheet s I Aug- 19, 1969 R. ,1. BROWN 3,461,825

SHEET-HANDLING APPARATUS Filed Oct. 11, 1967 v s Shets-Sheet 6 INVENTOR.

ROY J. BROWN /WWW ATTORNEYS United States Patent US. Cl. 11210 20 Claims ABSTRACT OF THE DISCLOSURE Sheet-handling apparatus capable of moving a flexible sheet from a first location to a second location while the sheet is vertically disposed and freely hangs from a first conveyor. Means is provided to move the sheet off and away from the first conveyor and onto a second conveyor which moves the sheet in a generally horizontal plane. The apparatus is especially adapted for making bags wherein a first sewing machine positioned at the first location stitches opposed side margins of the sheet after the latter has been folded upon itself and as the sheet is manually fed into the first sewing machine. A second sewing machine adjacent to the second conveyor stitches opposed end margins of the sheet as the sheet moves in the horizontal plane. Means is provided to align the end margins of the sheet when the latter is vertically disposed.

This invention relates to improvements in sheet handling equipment and, more particularly, to a machine for making bags from flexible sheet material, such as burlap or the like.

The apparatus of the present invention operates to move a flexible sheet along a first path from a first location to a second location while the sheet hangs freely in a substantially vertical plane. At the second location, the sheet, while still vertically disposed, is shifted laterally and then is moved along a second path with the sheet in a substantially horizontal plane or at least in an inclined position. A first conveyor engages an upper margin of the sheet and allows the latter to hang freely and move in the vertical plane. A transfer bar at the second location quickly moves the upper margin of the sheet laterally of and away from the first conveyor so that the sheet assumes a position in another vertical plane. A second conveyor then grasps the upper margin of the sheet and moves the latter in a substantially horizontal plane.

Adjacent to the transfer bar is a device for aligning a pair of adjacent vertically disposed marginal edges of the sheet while the latter is in a vertical plane. As the sheet moves from the vertical plane to the horizontal plane, the aforesaid marginal edges remain in alignment even though one edge is above the other.

While the apparatus of this invention may be adapted for a number of different uses, it is especially adapted for bag-making operations which require that a bag be made from a single sheet of bag material. Textile materials, such as burlap and other fabrics, can be used with the invention to make bags. Also, the invention can be used to make bags from synthetic materials, such as polypropylene or the like.

As used with the invention, a sheet is folded upon itself to present a pair of side marginal edge portions and a pair of end marginal edge portions. If the sheet is of a synthetic material suitable bonding means may be applied to the marginal edge portions. A pair of sewing machines are used for stitching the side and end marginal edge portions respectively if the sheet i a textile material and when the folded sheet is properly oriented relative to the sewing machines. In this way, the stitched sheet will form an open end bag whose one side and bottom are "ice stitched by the sewing machines and whose other side is formed by the fold line of the sheet.

The first sewing machine will be manually fed by an operator who folds a sheet so that the side and end marginal edge portions are adjacent to each other. Generally, the adjacent side margins of the sheet are stitched by the first sewing machine but the invention is constructed so that either pair of edge portions can be stitched by the first sewing machine. After the operator starts the sheet into the first sewing machine, further operations in handling the sheet are automatic and positioning of the sheet, aligning the end margins of the sheet, and stitching the end margins can all be done without operator attention. The invention is, therefore, adapted for the high volume production of bags with a minimum of manual operations.

Prior bag making machines which involve stitching a fabric sheet generally operate to move a sheet through the various steps of a bag making operation while the sheet remains in a substantially horizontal plane. A major problem stemming from the use of such machines is the difliculty in aligning the adjacent marginal edge portions of the sheet to be stitched. Since the sheet is horizontally disposed, one marginal edge portion overlies the other edge portion and the fabric must oftentimes be slightly stretched along its length to bring its marginal edge portions into alignment with each other. Such stretching is usually not done uniformly along the length of a sheet and tends to destroy the alignment so that the marginal edges become askew with respect to each other. Also, the friction forces between the engaging side portions of the sheet prevent the edges from becoming properly aligned since any movement of one side portion of the sheet usually causes some movement of the other side portion.

If the marginal edges are not properly aligned when they are stitched, the bag which is formed by the stitching operation may be rejected as not conforming to required standards. Generally, most bag standards require that the stitching line be uniformly spaced a minimum distance from adjacent marginal edges of the fabric sheet. If this standard is not attained, the bag will not have the proper strength characteristics and, if the standard is attained at the expense of forming the stitching line beyond the minimum distance from the marginal edge, the capacity of the bag will be reduced.

The present invention avoids these problems by hanging the sheet in a substantially vertical plane before a pair of marginal edge portions of the sheet are stitched, so that the edge portions can become properly aligned with each other without interference from friction forces between the opposite sides of the sheet. Also, this alignment is maintained as the sheet moves through a stitching station, whereby the sheet is stitched along a line which conforms to the required standards. To this end, the apparatus of the invention allows the bag to hang from and to be moved by a conveyor so that the edge portions to be stitched will be vertically disposed for alignment purposes. After the alignment has been made, the sheet is moved in the horizontal plane so that the aligned marginal edge portions can be stitched to form the corresponding extremity of the bag.

Bags of different sizes can be made by utilizing the teachings of this invention. Also, the invention provides for the stacking of completed bags so that the bags can be taken in a stack to a storage area or a point of use.

The primary object of this invention is, therefore, to provide improved sheet handling apparatus which advances a flexible sheet along a first path while the sheet hangs in a substantially vertical plane and then moves the sheet along a second path extending transversely of the first path so that a pair of opposed, adjacent marginal edge portions of the sheet can be readily aligned with each other when the sheet is vertically disposed and can be held in alignment as the sheet is horizontally disposed to permit the apparatus to be used for making bags of the type which are stitched along one side and across the bottom.

Another object of this invention is to provide a bag making machine which is capable of moving a flexible sheet in a vertical plane folded upon itself along a predetermined path of travel after a first pair of adjacent marginal edge portions of the sheet have been stitched together, so that a second pair of adjacent marginal edge portions of the sheet can be vertically disposed and can become aligned with each other before the sheet is moved in a horizontal plane with the second marginal edge portions disposed to be stitched as the sheet moves in the horizontal plane.

A further object of this invention is the provision of a bag making machine of the type described which is provided with an improved conveyor which can be releasably attached to an upper margin of a sheet to move the latter in a vertical plane whereby the sheet will hang from the conveyor to permit alignment of the aforesaid marginal edge portions and allow the sheet to be released from the conveyor after the alignment has been completed.

Yet another object of this invention is to provide a bag making machine of the aforesaid character wherein the machine is provided with an improved transfer mechanism for quickly moving the sheet laterally of and away from the conveyor, so that the sheet can become coupled to a second conveyor and allow the first conveyor to operate continuously to successively advance a number of sheets to the transfer region.

A further object of this invention is to provide a bag making machine of the type described wherein the machine has improved alignment means across the path of travel of the suspended sheet which is capable of forcing the leading marginal edges of the sheet toward and into engagement with vertically spaced stops, when the sheet is vertically disposed, so that the marginal edges will become aligned with each other to permit the respective margins of the sheet to be stitched together as the sheet is moved in a horizontal plane through a sewing machine disposed in the path of travel of the aligned marginal edges.

Other objects of this invention will become apparent as the specification progresses, reference being had to the accompanying drawings for an illustration of a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a front elevational view of the bag sewing machine of the present invention;

FIG. 2 is an elevational view of one side of the machine looking in the direction of line 22 of FIG. 1;

FIG. 3 is an elevational view of the opposite side looking in the direction of line 33 of FIG. 1;

FIG. 4 is a top plan view of the machine looking in the direction of line 4-4 of FIG. 1;

FIG. 5 is a fragmentary cross section view taken along line 55 of FIG. 4;

FIG. 6 is an enlarged cross sectional view taken along line 66 of FIG. 1;

FIG. 7 is an enlarged fragmentary front elevational view of the transfer bar forming a part of the apparatus;

FIG. 8 is an enlarged top plan view of the apparatus;

FIG. 9 is an enlarged fragmentary side elevational view of part of the machine;

FIG. 10 is a top plan view of the structure shown in FIG. 9; and

FIG. 11 is a vertical section showing the way the sheet becomes attached to the first conveyor.

GENERAL OPERATION The bag sewing machine of the present invention, broadly denoted by the numeral 10, includes a table-like support 12 adapted to be disposed on a floor or other supporting surface. Machine 10 has two

sewing machines

14 and 16 of substantially conventional construction, the machines being adapted to stitch first and second pairs of adjacent marginal edge portions of a sheet folded upon itself, whereby the stitched edge portions will form one side and the bottom of an open top bag. Machine 10 is essentially automatic except that an operator stationed adjacent to sewing machine 14, feeds one pair of adjacent edge portions of the sheet into sewing machine 14. After the stitching of the sheet has commenced, a first conveyor or advancing means 18 engages the stitched margin of the sheet as it progressively moves out of and away from sewing machine 14, Conveyor 18 allows the sheet to hang freely and be disposed in a vertical plane.

The sheet is then advanced by conveyor 18 while hanging therefrom to a transfer location 20 adjacent to and extending longitudinally of a shiftable transfer bar 22 (FIGS. 4, 5 and 8). From the transfer location, the sheet is moved laterally by transfer bar 22 out of coupled relationship to conveyor 18 into coupled relationship with a second conveyor 24 which moves the sheet in a direction laterally of and away from transfer location 20 while the sheet is in a substantially horizontal plane. When the sheet is vertically disposed, its second pair of marginal edge portions are aligned by an edge aligning device disposed across the path of the hanging sheet. As the sheet is moved in the horizontal plane, these second marginal edge portions move through sewing machine 16 and are stitched together. A stacking device 26 adjacent to the downstream end of second conveyor 24 grips the completed bag and moves it to a stacking location at which it is dropped and stacked on bags previously mad:

An endless, flexible double belt unit 28 adjacent to sewing machine 14 has a generally horizontal stretch 30 for urging a sheet 34 along a horizontal path after a first pair of marginal edge portions of the sheet such as the side edge portions have been manually fed through sewing machine 14 and have been stitched together by the sewing needle 32. The operator guides sheet 34 into the path of needle 32 after folding the sheet upon itself to present the adjacent side marginal edge portions and the adjacent end marginal edge portions. Stretch 30 of belt unit 28 is vertically shiftable since the lower pulleys of unit 28 are mounted on a rotatable bar 37 (FIG. 9) pivoted on a shaft 39 extending outwardly from vertical plate 35 and carrying pulley 41. This movement accommodates sheets of different thicknesses. A spring 43 biases one end of bar 37 upwardly and a shiftable screw 33 provides for tension adjustment of belt unit 28. An idler pulley 45 carried on a bar 47 pivoted on shaft 49 serves to maintain tension on belt unit 28. Spring 51 biases bar 47 in a counterclockwise direction when viewing FIG. 9.

A thread cutting unit 53 is disposed on sewing machine 14 and includes a blade 55 secured to a shiftable piston rod 57 of a fluid actuated piston and cylinder assembly 59. Assembly 59 is controlled by a fluid valve (not shown) actuated by an electrical switch 61 secured to a bracket 63 having a slot 65. A bolt 67 extends through slot 65 and adjustably mounts bracket 63 on the end plate 69 of sewing machine 14. The cylinder of assembly 59 is also mounted in a suitable manner on end plate 69 so that blade 55 will move downwardly and against a butt plate (not shown) for severing a thread on the butt plate.

Switch 61 is actuated by an extension 71 extending laterally from one arm 73 of a crank 75 pivoted on bracket 63. The other arm 77 of crank 75 is pivoted on a vertical plate or shoe 79 which normally rests on the sheet supporting surface of sewing machine 14. Another arm 81 pivoted to bracket 63 and shoe 79 is disposed in parallelism to arm 77 so that the lower edge of shoe 79 remains parallel with the aforesaid sheet-supporting surface as the shoe is elevated when a sheet passes beneath it.

As shoe 79 is raised, extension 71 lifts the actuating arm 83 on switch 61 to actuate the same. This action lifts blade 55 away from the butt plate and, when shoe 79 is allowed to descend, the switch opens permitting a spring in the cylinder of assembly 59 to force piston rod 57 and thereby blade 55 downwardly, whereby the blade will cut the thread on the butt plate. Slot 65 in bracket 63 allows the position of shoe 79 to be adjusted so that the length of the thread tailing from sheet 34 (after the latter has been stitched by sewing machine 14) to be varied.

Sewing machine 16 also has a thread cutting unit substantially identical to cutting unit 53. However, the electrical switch of the thread cutting unit corresponding to sewing machine 16 will not only cause the shifting of the cutting blade but will operate to energize and deenergize the motor which drives sewing machine 16. The operation of this drive motor will be a function of the location of a sheet to be stitched thereby so that sewing machine -16 will be turned on before the sheet reaches its sewing needle.

First conveyor 18 comprises an endless, flexible belt 40 having a plurality of sharp pins 42 projecting outwardly therefrom in the manner shown in FIGS. 4 and 8. Belt 40 passes about a number of pulleys which are arranged to form a pair of stretches 44 and 46 (FIG. 4) with stretch 44 being substantially parallel to stretch 30 of belt 28 and stretch 46 extending along and through transfer location 20. Belt 40 is driven in the direction of arrow 48 (FIG. 8) by a motor (not shown) secured to support 12 and coupled to the shaft 50 on which is mounted a pulley 52 about which belt 40 is disposed. Belt 40 will move at a predetermined speed sufficient to allow a sheet 34 to be separated therefrom by transfer bar 22 without having to stop belt 40.

As belt 40 rounds a second pulley 54, the pins 42 penetrate a vertically disposed portion 83 (FIG. 11) of sheet 34 as the latter moves away from sewing needle 32. Portion 83 is presented to pins 42 because a first plate 85 having an inclined edge 87 lifts the stitched margin of the sheet and a guide bar 89 having a pair of spaced, angled surfaces 91 at one end thereof urges portion 83 laterally and into coupled relationship to pins 42. Surfaces 91 are across the path of travel of portion 83 and the latter is limited in its upward movement over plate 85 by a knurled disc 93 mounted on shaft 49 and is rotatable therewith. Plate 85 has a slot 95 (FIG. 9) for permitting pins 42 to extend in proximity to portion 83. Guide bar 89 has an edge 97 (FIG. which holds portion 83 on pins 42 as the sheet moves along stretch 44.

As sheet 34 moves along stretch 44, it hangs freely from belt 40 in a generally vertical plane. No structure intersects this vertical plane so that the sheet will move uninterruptedly under the influence of belt 40.

FIGS. 4 and 8 show how belt unit 28 is moved in response to the movement of belt 40. Shaft 56 for pulley 54 has a bevel gear 58 in mesh with a second bevel gear 60 secured to shaft 49 on which is mounted a pulley 64 coupled with belt unit 28 (FIG. 2). Disc 93 (not shown in FIGS. 4 and 8) also rotates with pulley 64.

Guide bar 89 has a curved portion 99 which follows the path of belt 40 as the latter moves about a third pulley 70. As pins 42 move around pulley 70, they spread apart so as to more assuredly hold sheet on belt 40. Tension in belt 40 can be controlled by a fourth pulley 72 carried on a threaded shaft 74 shiftably mounted in a sleeve 76 secured to the upper surface 78 of a support plate 80 forming a part of support 12.

Transfer bar 22 includes three articulated

sections

82, 84 and 86, section 84 being hingedly connected to section 82 and section 86 being hingedly connected to section 84 as shown in FIGS. 5 and 7. Section 82 is secured in any suitable manner to the upper surface 78 of support plate 80 (FIG. 5) so that the three sections extend longitudinally of stretch 46 of belt 40. An extension 88 is secured to section 86 in any suitable manner adjacent to the central part thereof and the extension is secured to the outer end of a piston rod 90 forming a part of a fluid actuated piston and cylinder assembly 92 mounted in any suitable manner on upper surface 78. Thus, as piston rod 90 moves toward

sections

82, 84 and 86, the sections are moved from collapsed or retracted positions to expanded positions; conversely, movement of the rod 90 in the opposite direction causes the sections to retract into the positions thereof shown in FIG. 5.

Section 86 has a plurality of teeth 94 on the outermost longitudinal edge thereof. These teeth are adapted to move into engagement with sheet 34 and beneath stretch 46 so as to force sheet 34 off and away from pins 42 and into coupled relationship with second conveyor 24 when rod 90 is forced out of its cylinder. As shown in FIG. 7, each tooth has an inclined edge and an edge perpendicular to the path of travel of belt 40 past transfer bar 22. This tooth shape allows for more effective removal of sheet 34 from pins 42 since the teeth are effectively pointing downstream of the path of belt 40 and allow the sheet to be moved laterally of this path even though the sheet will continue to move under the influence of its own inertia longitudinally of this path.

FIG. 5 illustrates that section 86 of bar 22 is inclined relative to pins 42 to cause rapid separation of sheet 34 therefrom.

Sections

82, 84, and 86 of transfer bar 22 can be made up in segments as shown in FIG. 7, whereby the length of bar 22 can be increased or decreased as desired to adapt machine 10 for making bags of different sizes. In the alternative, each of the sections of bar 22 can have a fixed length to accommodate bags of both large and small sizes.

A channel member 103 (FIGS. 9 and 10) attached by a hinge to a bracket 107 overlie stretch 46 of belt 40 and has a lip 109 which holds sheet 34 on pins 42 as the sheet moves toward location 20. A spring 111 biases channel member 103 downwardly but allows the latter to swing upwardly when transfer bar 22 displaces sheet 34 to one side of stretch 46.

An edge aligning device 96 is secured to support 12 adjacent to one end of transfer location 20 in alignment with the path of travel of sheet 34. Device 96, shown in detail in FIG. 6, includes a pair of

side plates

98 and 100 which are spaced apart and are disposed on opposed sides of the path of travel of sheet 34. These plates are connected together by threaded fasteners 102 (only one of which is shown in FIG. 6). Each fastener 102 has a cylindrical spacer 104 thereon in the region between

plates

98 and 100 and the various spacers 104 are vertically aligned and serve as stops for the leading marginal edges of

side portions

34a and 34b of sheet 34. An extension plate 101 (FIGS. 2 and 6) extends downward from

plates

92 and 100 and is vertically aligned with stops 104. Plate 101 serves as an abutment for the lower leading edge portions of sheet 34 to prevent the latter from becoming askew at its lower regions when its upper leading edge portions engage stops 104.

Plates

98 and 100 are relatively convergent as spacers 104 are approached and also form a fluid passage 106 which is in fluid communication with the regions between spacers 104. Passage 106 is also in fluid communication with a fluid chamber 108 in housing 110 having an opening 111 connecting passage 106 and chamber 108. A second opening 112 in housing 110 places chamber 108 in fluid communication with a conduit 114 leading to the air intake side of a blower 116 having an exhaust outlet 118. A motor 120 operates blower 116 and evacuates chamber 108 and thereby passage 106 so that a suction force will be exerted on the marginal edges of

side portions

34a and 34b when the latter are adjacent to spacers 104. The edges are thus drawn against spacers 104 and are aligned thereby. A pair of baflles 122 mounted in chamber 108 are disposed to decrease the speed of the air flow moving between openings 111 and 112, while maintaining the speed of the air flow between spacers 104 at a desired maximum value. To this end, baflles 122 are divergent as Opening 112 is approached.

In practice, transfer bar 22 will be shifted in a direction to move sheet 34 off pins 42 before the sheet has reached stops 104. However, the inertia of the sheet and the suction force exerted by device 96 will assure that the leading edges of the sheet will move into the positions shown in FIG. 6. An electric eye or a suitable limit switch can be used to actuate assembly 92 to cause the movement of transfer bar 22.

Second conveyor 24 includes a series of upper belt and pulley assemblies 124 and a series of lower belt and pulley assemblies 126, there being an assembly 126 for each assembly 124, respectively. Each assembly 124 includes a belt 128 coupled with pulleys carried by a vertically disposed plate 130 secured in any suitable manner to sup port 12. Each belt 128 has a lower horizontal stretch 132 which is normally in juxtaposition to and overlies the upper horizontal stretch 134 of a corresponding belt 136 on an assembly 126. Thus, stretches 132 and 134 of each pair of

assemblies

124 and 126 provides means for gripping a portion of sheet 34 to advance the same in a substantially horizontal plane in the direction of arrow 138 (FIG. the direction of movement of both

stretches

132 and 134. The sheet is thereby conveyed away from transfer location in the horizontal plane and toward stacker 26. Each belt 136 is coupled to a pair of spaced

pulleys

140 and 142 which are rotatable about respective axes disposed below a top plate 144 having an opening 146 for pulley 140 so that the corresponding upper stretch 134 of belt 136 will be supported by plate 144, to prevent sagging of this stretch.

A drive shaft 148 (FIGS. 2 and 5) common to each assembly 124 (FIG. 4) extends parallel to transfer location 20. Similarly, a drive shaft 150 parallel to shaft 148 and disposed therebelow is common to assemblies 126. A drive motor 152 mounted in any suitable manner on support 12 is coupled by an endless, flexible drive chain 154 to shaft 150 and the latter is, in turn, coupled by meshed spur gears 156 and 158 to drive shaft 148. Thus, these shafts are rotated in opposite directions so that stretches 132 and 134 move in the direction of arrow 138.

Second conveyor 24 also includes a nip roll means for forcing sheet 34 into driving relationship with belts 136 after the sheet has been separated from belt 40 by transfer bar 22. To this end, a pair of cranks 160 are rotatably mounted at spaced locations on shaft 148 (FIG. 4). Each crank 160 includes a pair of rigidly

interconnected arms

162 and 164, arm 162 having a shaft 166 rotatably mounted thereon with the shaft having a number of nip rolls 168 rigidly mounted at spaced locations thereon for rotation therewith. As cranks 160 rotate in a clockwise sense when viewing FIG. 5, the nip rolls are caused to move into engagement with sheet 34 after the latter has been separated from belt 40 by transfer bar 22 and the nip rolls force the sheet into engagement with the moving I belts 136. Since shaft 166 is freely rotatable on arms 162, the sheet is forcibly driven between

stretches

132 and 134 of

belts

128 and 136 respectively so that the sheet is gripped by these stretches and conveyed toward stacker 26.

To rotate cranks 160, a pair of piston and cylinder assemblies 170 is provided. Each assembly 170 has a piston rod 172 whose outer end is pivotally coupled to the outer end of the corresponding arm 164 (FIG. 5). Thus, as assemblies 170 are simultaneously energized, cranks 160 will rotate together to cause nip rolls 168 to move simultaneously into engagement with the sheet. There will be an extremely small time delay (of the order of milliseconds) between the time when assembly 92 is actuated and assemblies 170 are actuated. Thus, the sheet is engaged, by the nip rolls at the proper time to assure that the sheet will be coupled to conveyor 24.

Means is provided for second conveyor 24 to hold the aligned marginal edges of

side portions

34a and 34b together as the sheet is moved by belt stretches 132 and 134 toward stacker 26. To this end, a double belt unit 174 having a pair of endless, flexible belts 176 extends longitudinally of second conveyor 24 and has an extremity adjacent to alignment device 96. Each belt 176 has a lower stretch 177 which forces the side portions 34a and 341) into engagement with moving belt structure (not shown) which extends along the upper surface of top plate 144 and terminates just short of the sewing needle of sewing machine 16. Thus,

side portions

34a and 34b will remain properly aligned with each other as they pass through sewing machine 16. One of the nip rolls 168 (FIG. 1) is positioned to force the marginal edge portions of the sheet into sliding engagement with the upper surface of top plate 144. Also, a weighted roller 179 carried by a freely pivoted bar 181 forces stretches 177 downwardly to assure that the sheet will be properly driven through sewing machine 16.

Sewing machine 16 is also of conventional construction and is driven by a belt and pulley assembly 178 connected to the drive shaft (FIG. 3) of a motor (not shown). Control means of the type utilized with cutting unit 53 is provided to actuate sewing machine 16 as a sheet 34 is moved toward the same. Thus, sewing machine 16 does not have to be operated continuously.

Stacker 26 at the downstream end of second conveyor 24 is of any suitable type. For purposes of illustration, it has a number of pairs of arms 182 and 184 with arm 182 of each pair being movable beneath a moving sheet 134 to force the sheet into engagement with the corresponding arm 184. In this way, the sheet is gripped between each pair of arms and the latter are then moved with the other pairs of arms as a unit further downstream with respect to second conveyor 24 to carry the sheet therewith, whereby the sheet may be deposited in a stack to the rear of machine 10.

A first fluid actuated piston and cylinder assembly 186 causes arms 182 to move so that they underlie sheet 134 and force the latter into engagement with respective arms 184. A second fluid piston and cylinder assembly 188 then causes the pairs of arms to move as units so as to draw the sheet away from machine 10 to the stacking location. To this end, a crank unit 190 having a first arm 192 pivotally connected to the outer end of a piston rod 194 forming a part of assembly 188 has a second arm 196 rigid to arm 192 for pivotally mounting assembly 186 thereon for movement rearwardly of machine 10 as arm 192 rotates in a clockwise sense when viewing FIG. 3 about an axis through a. pin 198 secured to a fixed arm 200. A link 202 coupled to assembly 186 causes the latter to swing toward the horizontal as it moves rearwardly of the machine. Arms 182 and 184, mounted on

shafts

204 and 206 respectively which extends laterally from assembly 186, will have previously engaged and gripped sheet 34 before the rearward movement of assembly 186 under the influence of crank 190. Thus, the movement of crank unit 190 assures rearward movement of a sheet 34 gripped by arms 182 and 184.

DETAILED OPERATION Machine 10 is initially placed in operation when an operator positioned adjacent to sewing machine 14 feeds a first pair of adjacent marginal edge portions of sheet 34 folded upon itself toward sewing needle 32 of sewing machine 14. Generally, a stack of sheets will be located adjacent to the operator position and the operator will take the sheets, one by one, and fold each sheet upon itself so that the marginal edge portions which will define the side of a bag are in juxtaposition to each other. As these marginal edge portions are fed through sewing machine 14, they are stitched along a line uniformly spaced from the edges of the side marginal edge portions of the sheet. The operator can present the marginal edge portions to sewing machine 14 in a manner to provide a particular seam for the bag, such as an export seam or the like. A guide may be provided as part of sewing machine 14 to direct the marginal edge portions of the sheet therethrough.

As soon as the sheet begins to move out of and away from sewing machine 14, the stitched margin of the sheet is moved by surfaces 87 and 91 (FIGS. 9, and 11) into coupled relationship to pins 42 and the latter carry the sheet successively along stretches 44 and 46 of belt 40. The belt will be continuously moving and its speed will be correlated with the speed of movement of belt 28 which facilitates the movement of the sheet through sewing machine 14.

As pins 42 advance the sheet toward location 20, the sheet freely hangs from belt 40 in a vertical plane. The end marginal edge portions which, when stitched together, will define the bottom of a bag, move in advance of the remainder of the sheet and eventually move into proximity to spacers 104 in the manner shown in FIGURE 6.

Transfer bar 22 has an electric eye or a limit switch (not shown) associated therewith for actuating piston and cylinder assembly 92 as a function of the position of the sheet at location 20. Thus, when the sheet trips the limit switch, transfer bar 22 is immediately shifted toward second conveyor 24 and forcibly engages the sheet to cause the latter to shift away from pins 42 and toward second conveyor 24. This lifts channel member 103 which had previously operated to hold the sheet on pins 42 as the sheet moved toward location 20. The end marginal edges of

side portions

34a and 34b will then become aligned with each other under the influence of device 96.

Within a relatively short time after transfer bar 22 begins to move laterally, piston and cylinder assemblies 170 are energized to cause cranks 160 to rotate about shaft 148 in a clockwise sense when viewing FIGURE 5. Thus, nip rolls 168 force the sheet into engagement with belts 136 at least until the sheet passes between

stretches

132 and 134. When this occurs, the sheet is effectively gripped and caused to move toward stacker 26. The nip roll corresponding to belts 176 forces the aligned marginal edge portions into engagement with the belt structure extending along surface of plate 144 and, to facilitate this action, a curved extension defining a convex surface can be provided on plate 144 to more assuredly maintain the marginal edge portions in alignment with each other.

The sheet is conveyed toward stacker 26 and the end marginal edge portions are moved in stitching relationship through sewing machine 16. Thus, the end margin of a bag is formed with the stitch line being uniformly spaced from the end marginal edges of the sheet.

A limit switch will also be provided to actuate stacker 26 so that arms 182 and 184 thereof will move into gripping relationship with the sheet as the latter moves downstream of second conveyor 24. Stacker 26 will then advance the sheet to a location away from machine 10, whereupon arm-s 182 and 184 will separate to allow the sheet to be dropped onto a stack or other suitable structure.

Immediately after one sheet is fed through sewing machine 14, the operator can prepare a second sheet to be stitched by sewing machine 14 and the second sheet can be stitched as the first sheet is moving toward location 20. In this way, a relatively large number of sheets can be processed in a minimum of time with the only manual step being to feed the sheet initially through the first stitching station.

The way in which a sheet is separated from pins 42 also contributes to the relatively high volume production of bags by machine 10. This is due to the fact that transfer bar 22 shifts a sheet laterally of belt 40 even while the latter continues to move so that one sheet is displaced laterally of location as a succeeding sheet carried by pins 42 moves toward this location. Thus, one sheet may be moved into coupled relationship with second conveyor 24 as the succeeding sheet is advancing toward location 20.

Machine 10 can continue to operate in the above manner so long as sheets are fed by the operator through sewing machine 14. Except for the step of feeding sheets into sewing machine 14, the operation of machine 10 is essentially automatic and the bags formed thereby will conform to desired standards.

While one embodiment of this invention has been shown and described, it will be apparent that other adaptations and modifications of this device can be made without departing from the true scope of the invention.

What is claimed is:

1. A machine for making a bag from a sheet of bag material comprising: a first sewing machine for stitching a first pair of adjacent marginal edges of the sheet to form one margin of a bag and to present a second pair of adjacent marginal edges of the sheet extending laterally from said one margin; means adjacent to the first sewing machine for engaging a margin of the sheet as the latter move away from the first sewing machine and for advancing the sheet to a location remote therefrom with the sheet hanging from said engaging and advancing means and disposed in a generally vertical plane; means at said location for separating the sheet from said engaging and advancing means; a second sewing machine spaced from said location; and means adjacent to said location for conveying the sheet in a plane transverse to the vertical plane past said second sewing machine with said second marginal edges in a position to be stitched thereby after said sheet has been separated from said advancing means, whereby a second margin of the bag is formed.

2. A machine as set forth in claim 1, wherein said separating means is disposed to shift the sheet laterally of the path of travel of said engaging and advancing means and into coupled relationship to said conveying means.

3. A machine as set forth in claim 1, wherein said conveying means includes structure for holding said second marginal edges in alignment as said sheet is conveyed past said second sewing machine.

4. A machine as set forth in claim 1, wherein said conveying means includes belt structure movable away from said location and bearing structure for forcing the sheet into engagement with said belt structure after said sheet has been separated from said advancing means.

5. A machine as set forth in claim 1, wherein said engaging and advancing means includes first endless belt structure having a first horizontal stretch and mean for releasable connection with said one margin of the sheet, said separating means including a bar mounted for movement laterally of the path of travel of said first stretch and being forcibly engageable with the sheet to urge the latter away from said first stretch as the sheet hangs from said engaging and advancing means, said conveying means including second endless belt structure having a second horizontal stretch extending laterally of and movable away from said path, and nip roll means adjacent to said second stretch for forcing the sheet into engagement therewith after the sheet has been urged away from said first stretch.

6. A machine as set forth in claim 1, wherein is included structure in the path of travel of the sheet as it moves away from said first sewing machine for forcing the sheet toward and into coupled relationship to said engaging and advancing means.

7. A machine as set forth in claim 6, wherein said engaging and advancing means includes an endless belt having a number of spaced pins extending outwardly from one side thereof, said structure including a first member having a surface for lifting said one margin of the sheet to present a vertically disposed face, and a second member having a surface for progressively moving said vertically disposed face toward said pins, whereby the sheet will engage the pins at said vertically disposed face and will be carried by the belt to said location.

8. A machine as set forth in claim 1, wherein is provided means adjacent to said first sewing machine for cutting the thread thereof as a function of the position of the sheet relative thereto and after said one margin has been stitched thereby.

9. A machine for making a bag from a sheet of bag material comprising: means for securing a first pair of adjacent marginal edge portions of the sheet together to form one margin of a bag and to present a second pair of adjacent marginal edge portions of the sheet extending laterally from said one margin; means adjacent to said securing means for engaging the sheet as the later moves away from the securing means and for advancing the sheet to a location remote therefrom with the sheet hanging from said engaging and advancing means and disposed in a generally vertical plane; means at said location for separating the sheet from said engaging and advancing means; means spaced from said location for connecting the second pair of marginal edge portions together; and means adjacent to said location for conveying the sheet in a plane transverse to the vertical plane past said connecting means with said second marginal edge portions in a position to be connected thereby after said sheet has been separated from said engaging and advancing means, whereby a second margin of the bag is formed.

10. A machine for making a bag from a flexible sheet of bag material folded upon itself to present a pair of adjacent side margins and a pair of adjacent end margins comprising: a first sewing machine for stitching said side margins of the sheet to form one side of a bag; means adjacent to the first sewing machine for engaging the stitched side margins of the sheet as it moves away from said first sewing machine and for advancing the sheet to a location remote from said first sewing machine as the sheet hangs from said engaging and advancing mean in a generally vertical plane; means adjacent to said first sewing machine for urging the stitched side margins into coupled relationship to said engaging and advancing means; means adjacent to said location for aligning the end margins of the sheet with each other as the sheet is vertically disposed; means at said location for separating the sheet from said engaging and advancing means; a second sewing machine spaced from said location; and means adjacent to said location for conveying the sheet in a generally horizontal plane past said second sewing machine with said end margins disposed to be stitched by the second sewing machine, whereby one end of the bag is closed.

11. A machine as set forth in claim 10, wherein said aligning means comprises a suction device.

12. A machine as set forth in claim 11, wherein said device has means defining a pair of vertically spaced stops and a vacuum chamber communicating with the space between the stops, said engaging and advancing means being disposed to shift the sheet toward said device with the end margins of the sheet substantially vertically disposed and horizontally aligned with the stops.

13. A machine as set forth in claim 10, wherein is provided means adjacent to said engaging and advancing means for releasably holding the sheet thereon as the sheet is moved to said location.

14. A machine as set forth in claim wherein said separating means includes a shiftable transfer bar, actuatable power means coupled with the transfer bar for shifting the latter transversely of the path of travel of the engaging and advancing means and into forcible engagement with the sheet to separate it from the engaging and advancing means, and means responsive to the position of the sheet along the path of said engaging and advancing means for actuating said power means.

15. A machine as set forth in claim 14, wherein said transfer bar has a plurality of sheet-engaging teeth, each tooth having a pair of convergent edges with one edge extending longitudinally of and at an angle to said path of travel and a second edge substantially perpendicular to said path.

16. In a sheet handling machine a first conveyor having means for releasable engagement with a sheet along one margin of the latter to cause the sheet to hang freely in a generally vertical plane, said conveyor being disposed for advancing the sheet along a first, generally horizontal path as the sheet hangs from the first conveyor; means adjacent to said first conveyor for moving the sheet laterally of said first path and away from said first conveyor after the sheet has been moved through a predetermined distance along said first path; and a second conveyor having means for engaging said sheet to move the latter in a generally horizontal plane along a second path extending laterally from the first path.

17. In a sheet handling machine: a first conveyor having means adapted to engage one margin of a sheet to permit the sheet to hang freely in a generally vertical plane, said conveyor being disposed to move the sheet along a first path of travel as the sheet hangs from the conveyor; a device adjacent to said first path of travel for aligning a pair of adjacent end marginal edges of the sheet when the sheet is vertically disposed; means on one side of said first path for urging said sheet laterally of and away from said first conveyor to separate the sheet therefrom; and a second conveyor extending laterally of said first path and disposed for movirig the sheet along a second path of travel with said sheet disposed in a substantially horizontal plane, said urging 'means being disposed to move said sheet into coilipled relationship with said second conveyor, whereby the sheet move along said second path.

18. In a sheet handling machine, structure for aligning a pair of adjacent, vertically disposed marginal edges of a movable sh'eet when the latter is disposed in a subs-antially vertical planefcomprising: means defining a pair of vertically spaced stops adapted to be disposed in the path of travel of the sheet; and means coupled with the space between said stops for evacuating said space to thereby cause said edges of the sheet to be urged toward said stops by suction.

19. In a machine as set forth in claim 18, wherein said evacuating means includes a vacuum chamber adapted to be coupled to a vacuum source and being in fluid communication with said space, and wherein is included guide structure for directing said sheet toward said stops.

20. In a machine as set forth in claim 19, wherein said guide structure includes a pair of relatively convergent plates, and wherein is included a pair of spaced bafiies within said chamber and being relatively convergent as said stops are approached.

References Cited UNITED STATES PATENTS 2,630,086 3/1953 Kindseth et al 1l211 3,032,341 5/1962 Reist 27179 3,039,409 6/1962 Cordle 112l1 3,208,416 9/ 1965 Davis 112-11 3,224,394 12/1965 Dobner et a1 112-10 3,345,963 10/1967 Shoaf 271-79 X 1,738,186 12/1929 Krasa 112-252 ALFRED R. GUEST, Primary Examiner