JPH034026B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus and method for manufacturing thermoplastic bags.

Machines for producing bags from thermoplastic web material come in a variety of configurations, depending on the size and type of bag to be produced, and are accommodating the thickness of the material and its chemical composition. Some types of bag making machines are equipped to make certain types of bag, such as welded sides or welded bottoms; can be accomplished by replacing certain elements.

The purpose of advances in bag making machinery is to reduce the time required to make bags, either directly or indirectly. The most important point to reduce the time of the bag making cycle is that the bag making machine is provided in such a way that the bags are accumulated in successive and orderly piles, each pile containing a predetermined number of bags. The point is that it practically completely depends on whether or not it is. Recently attempted methods for obtaining counted and registered deposits include:
It uses a conveyor that accumulates bags known as ivy as a pile. Such an accumulation conveyor basically carries multiple sets of wickets.
The bag includes a pin that is successively placed at the deposition station and remains at the station until a predetermined number of bags are deposited on the pin. According to this method, each bag is provided with a pair of holes that correspond to the wicket pin spacing. Once the predetermined quantity of bags has been accumulated, the advance of the web is stopped and the conveyor carrying the pin sets transports the completed bag stack away from the stacking station, and then the conveyor carrying the pin sets transports the completed bag stack away from the stacking station, and then the conveyor carrying the pin sets transports the completed bag stack away from the stacking station, and then the conveyor carrying the pin sets transports the completed bag stack away from the stacking station. is placed on the deposition station. The problems of wind friction have little effect on the successful deposition of bags, and hundreds of low-gauge, high-density polyethylene bags can be deposited quickly and accurately, making it easy to use wicket pins. Machines using type deposition equipment are very widely used.

Apparatus for processing a flat thermoplastic tubular film drawn from a feed web roll at a sealed cutting station 66 to form a web piece of a predetermined size sufficient to be divided into two bags, the apparatus comprising: Each web piece is successively conveyed through a rotary transfer path onto a supporting wood block 174 provided in the rotary transfer path, and the web pieces are transported so that the splittable bags hang downwardly over both sides of said support blocks. A bag making apparatus is provided which features a holding device 84 on pins 90 secured to the support block along the central region between the divisible bags.

When manufacturing bags from tubular films, considerable advantages arise from printing on one or both sides of the film or web. Specifically, the design printed by the printing press can be doubled on both sides of the longitudinal centerline of the web. This is because a machine constructed in accordance with the principles of the present invention is capable of producing two bags from a piece of web.

The bag production speed achieved by the apparatus of the invention is twice the operating cycle time of the machine;
The physical properties of the material, such as lack of stiffness, are no longer a limiting factor in depositing bag pieces accurately and maintaining the deposit as a pile when transferred to another processing device. It stopped happening. More specifically, the apparatus of the present invention allows for controlled and rapid transport of a pile, and allows for a pile containing several hundred web pieces even when processing the thinnest, lowest density polyethylene. can be formed.

The main objective of the present invention is to double the maximum manufacturing capacity of conventional bag manufacturing equipment. To accomplish this, we have developed a series of equipment that can effectively process flat tubular web pieces large enough to be divided into two bags. By devising a particularly space-saving web deposition device 88, each formed web piece is transferred to the rotary transfer path 8.
6 onto supporting wood blocks 174 provided in the rotary transfer path, and the web pieces are conveyed along the central area between the splittable bags so that the splittable bags hang downwardly over both sides of the support blocks. The bag is held on pins 90 which are secured to the support block, providing economical and efficient bag manufacturing.

The apparatus of the invention will now be described with reference to the accompanying drawings.

With combined reference to FIGS. 1A and 1B,
A web processing machine according to the invention generally has instruction number 2.
It is indicated by 0. The main components of the processing machine 20 are an unwinding stand 22 that rotatably supports a roll of thermoplastic material (hereinafter also referred to as web roll WR) on a shaft 24, and a thermoplastic film TF. a plurality of idle rolls 2 that guide the tension control mechanism 28 mounted on the frame 30.
Contains 6. The film is made up of several stationary idle rolls 3
2 and a plurality of idler rolls 34 mounted for rotation within a vertically movable crosshead 36. The crosshead is guided vertically by a tubular rod 38 through which a rope or cable 40 is threaded. The end of the cable 40 is coupled to a weight 42 and the cable 40 travels through a pulley 44 in a generally rectangular loop. The sum of the weights of roll 34 and crosshead 36 is weight 42
This weight difference causes the crosshead to descend, thereby applying tension to the thermoplastic film stretched between idler rolls 32 and 34. The thermoplastic film then passes through idler rolls 46, 48, 50 and is further directed towards perforation device 52. Perforation device 52 has a perforation wheel 54 and a web drive roll 56, with one drive roll 56 functioning as a platen roll for perforation wheel 54. The film then passes through a dancer device 58 which applies and maintains a predetermined amount of tension on the film portion downstream of the drive roll 56. A gusset forming device 60 is mounted between the idler rolls 46 and 48 and between the idler rolls 48 and 50, and the gusset forming device 60 bends both edges of the thermoplastic film inward. It operates in such a way that it goes in.

The film sent out from the dancer device 58 is
It passes over idle rolls 62 and between tension rolls 64. The tension roll 64 is a sealing roll 68,
and a sealed cutting station 66 having a vertically reciprocating sealing rod 70 located adjacent thereto. A sealing rod 70 is heated to perform a sealing cutting operation on the film to form uniformly sized web pieces.
A punch device 76 is positioned between the sealed cutting station 66 and the idler roll 62 and on the accessory section 72 of the bag forming machine 74. As will be described in more detail below, the punching device 76 is activated during web rest to form a four hole pattern in the central area of the film web.

The film sections emerging from the sealed cutting station 66 are supported by a series of laterally spaced belts 78 which travel on a generally triangular track formed by an idler pulley 80 and a drive pulley 82. . Once the web portion advancing from the sealing rod 70 is cut and sealed, it is immediately gripped by the radially extending arm 84 of the rotary transfer device 86. The structure and operating conditions of this rotary transfer device 86 are known. The arm 84 has a series of apertures that are connected to a vacuum source and provide a web gripping action when the apertures contact a portion of the web, ie, a piece of web. The web piece is thus rotated through substantially 180 degrees and placed on the deposition device 88. The depositing device 88 includes pins 9 spaced apart from each other and extending upwardly so as to form a pattern that substantially matches the hole pattern created by the punching device 76.
0 is supported. As can be seen with reference to FIG. 1B, such a deposition device 88 is connected to conveyor 9
The conveyor 92 is driven by an indexing drive 94 and travels along a path provided by an idler sprocket 96 and a drive sprocket 98. A cutting or joining device 102 is mounted along the upper run of the conveyor 92 and on the frame 100 . Such devices are provided for dividing the stack of web pieces into bags.

Once the predetermined quantity of web pieces has been deposited on the deposition device located at deposition station SS, the advancement of the thermoplastic film located upstream of the sealed cutting station 66 is temporarily stopped until the subsequent deposition device 88 reaches the deposition station SS. will be stopped. While a stack of web pieces is being formed on one of the deposition devices 88, the web pieces on the downstream deposition device located directly below the cutting device 102 are lowered by actuators 106 that are actuated at the same time. It is cut into parts by a knife 104 that is moved.

depositing web pieces from plastic film;
Although it is common practice to subsequently divide the web stack so that two bags are obtained from each piece of web, the present invention provides means for actively transporting the web and Register and deposit hundreds of web pieces as a complete stack by providing a deposition station that restrains the web pieces and the stack of webs after the deposition is complete, and then using a cutting mechanism or a cutting and joining mechanism. It becomes possible to index towards. Such mechanisms are sometimes referred to below as cutting and/or blocking mechanisms. The advantages of processing with the equipment exemplified below are that it is possible to process the thinnest, lowest density polyethylene films, and that it is possible to process very narrow lips.
For example, it is possible to form a bag with a lip of 25 mm or about 1 inch. If it is desired to produce a bag with a lip (this expression refers to a bag in which the opening edges of the bag are mismatched or spaced apart), the slitting device 108 is placed on the frame structure 30. Attach to. Figure 3 shows the slitting device 10.
8, the device 108 includes a support rod 110 supported by the frame 30 and a block 112 adjustably secured to the support rod. Attached to the block 112 is a laterally spaced knife 114 arranged to cut a layer of the tubular film, i.e. from said layer as a film strip 116;
Thus, a void 118 is created on one side of the initially cylindrical thermoplastic film. providing conventional equipment (not shown) such as a tube connected to a vacuum source;
The film strip 116 that is no longer needed can be disposed of.

FIG. 4 shows the operation of the gusset forming device 60 which is a feature of the present invention. The gusset forming device 60 is attached to the frame 3
The short shaft 1 is installed so that it can rotate freely at 0.
includes a wheel 120 fixed to 22; The wheels 120 have sloping edges to facilitate folding the web inward, one wheel engaging one edge of the film as it approaches the idler roll 48 and the other wheel engaging one edge of the film as it approaches the idler roll 48.
When moving away from the film, it engages with the other edge of the film. If desired, the gusseting device may include two stationary flat plates spaced apart from each other, with a wheel or other flat plate accommodated therebetween.

When forming other types of bags in which the edges of the opposite surfaces of the web where the mouth portions are formed coincide, the operation of the slit device 108 is stopped or removed, and the punching mechanism (fifth ) is activated to form mutually spaced dotted lines 124 in both layers of the thermoplastic film TF whose edges are folded. The central area of the film between the dotted lines 124 is the zone in which holes are drilled for web piece deposition, as shown in FIG. It is shown connected to plate 126 carrying 128. A conventional controller may be used to energize the actuator 125 and cause the hole punch to penetrate the thermoplastic film to obtain four through holes 130 in the void portion 118 of the film. This drilling operation is performed while the web movement is temporarily stopped in order to perform a hermetic cutting operation on the web.

When a thermoplastic film with folded edges is fed by a tension roll 64 between a sealing roll 68 and a sealing rod 70 (FIG. 7), the longitudinal dimension of the web piece WS is such that the thermoplastic material It is determined by the extent to which it is pulled out towards 86. In FIG. 7, the web piece can be seen to include four holes 130, folded side edges 132, and a leading-trailing sealing portion 134. The thermoplastic film shown in FIGS. 6 and 7 has voids 118 created by removing film strip 116 with knife 114. If the apparatus is used to form bags with uniform edges, the thermoplastic film will include perforated dotted lines 124 and four holes 130 in each web piece.

As mentioned earlier, the sealing roll 68 and the sealing rod 7
The portion of the thermoplastic film emerging from the zero gap is supported by a series of laterally spaced belts 78, and when the film is sealed and cut, the web piece is
It is captured by a pair of laterally spaced arms 84. Arm 84 is located proximately below the web piece and rotates counterclockwise as viewed in FIGS. 1B and 2 to engage and hold the web piece. This is because arm 84 is hollow and the hollow portion is connected to hollow hub 136 which is frozen to a vacuum source mounted on shaft 137.
As each pair of arms approaches the transfer station TS, the web pieces are captured by a deposition device 8 located at the deposition station SS as shown in FIG.
8. Web pieces are accumulated on the deposition device until this predetermined quantity is accumulated. The expected number of such web pieces is determined by an operator driving the indexing drive 94 to move the stacking device 88 on the upper run of the conveyor 92 to the cutting device or the cutting and joining device 10.
2 by using a conventional counting mechanism that conditions the intermittent rotation of the web feeding pull roll 64 to be stopped for a sufficient period of time so that the web can be moved towards 2. A subsequent empty deposition device then reaches the deposition station SS.

Web pieces continue to be deposited on each deposition device 88, but the deposition operation is interrupted when a predetermined amount of web pieces have been deposited on one deposition device. When the deposition device carrying a sufficient number of web pieces reaches directly below the apparatus 102, the web pieces are divided along a line CP (FIGS. 9 and 10) located midway between edges 132. Ru. While this splitting operation is being made, a web piece deposition operation is performed on a subsequent deposition device 88.

Figures 9 and 10 illustrate two types of bags formed in accordance with the embodiment of the apparatus described above.

FIG. 9 shows a bag with a lip that does not match the upper margin forming the mouth of the bag. This is due to the removal of strip 116 to provide void 118.

FIG. 10 shows the shape of the web piece when the perforation device 52 is operated to create dotted lines, or perforations 124. When the web piece is divided into individual bag piles along line CP, the edges of the bags coincide because dotted lines 124 are formed on both panels of the web.

FIG. 11 shows the construction of an alternative embodiment of a transfer mechanism 86, which has the ability to handle laterally large web pieces WS and also provides stability to the web pieces while transferring them. This can be controlled as well as maintained. Such control is 4
This is achieved by two hubs 136 and associated radially extending arms 84 mounted on shafts 137. As the arm 84 engages and transports the web piece WS, it captures the web piece in laterally evenly spaced areas, thereby ensuring secure retention of the wider web piece.

If it is desired to process a web from a roll of flat, single-ply material, the edges of both sides of the web can be folded toward the longitudinal centerline of the web to form a gap 118 of the desired width. Conventional folding equipment that operates in the same manner can be used. Rolls of flat web where the edges of the web touch or overlap slightly and which are later punched through the panels on either side of the web to form a bag with matching edges are It has important advantages in printing. This is because the design to be printed appears on the panels on both sides of the bag, which simplifies the printing process.
Printing on both panels of a bag made of tubular material requires special printing procedures, such as passing the web through the printing device twice.

The device of the second embodiment, which as a whole constitutes only a part of the bag making machine, comprises bag pieces,
In other words, it merely performs the function of accumulating and cutting web pieces, and therefore, the bag pieces are placed in the first A.
It may be formed in the machine described in connection with the figures, or in any machine suitable for producing web pieces as described above.

Parts similar to those in the first embodiment will be given the same reference numbers, and the description will not be repeated.
The main difference from the first embodiment is that in the second embodiment each bag piece is transferred from a rotary transfer device 86 to a conveyor 92.
A holding device is employed which holds the bag piece in place immediately after it has been transferred upwards. The belt conveyor 78 includes a rotary transfer device 8 in FIG.
A gap 79 is provided to facilitate arm 84 of 6 to lift the bag piece.

A deposition device 188 is used instead of the deposition device 88 of the first embodiment. The deposition apparatus 188 is shown schematically in FIGS. 12 and 13, and in detail in FIGS. 14 and 15. Each deposition device 188
has a fixing device 180 for fixing a plate 192, which is rigidly connected to an upwardly bent end stop or guide 194. The plate 192 has a downwardly sloped edge portion 196 (with respect to the direction of conveyor travel) at its front end. The part of the bag piece located on the edge part 196 can cooperate with a clamp 198 which is pivoted at a distance from said edge part and is formed as a U-shaped piece of wire. Clamp 198 is rigidly connected to a J-shaped rod 200, with a longer extension of rod 200 coupled to the free end of U-shaped clamp 198. A helical spring 202 surrounds and acts on rod 200, which biases the clamp toward edge portion 196. The clamp can be retracted from the edge 196 by a pneumatic or hydraulic actuator 204 via a transverse plate 206 mounted on the free end of the piston rod 208 of the actuator.

When each deposition device 188 reaches the deposition station SS, the deposition device 188 is connected to a pair of pneumatic actuators 2.
10 and reach a position where it cooperates with 10. Pneumatic actuator 210
The cylinder 212 of is rigidly mounted on a portion of the frame 214 of the device. The piston rod 216 of each actuator has an end 218 formed of or coated with a friction material to aid in gripping the uppermost bag piece of the stack. do.

The actuator 210 operates in accordance with a controller (not shown), which is adapted to bias the actuator 210 in response to the angular position of the rotary transfer device 86.

When the machine is operated, one of the deposition devices 188 is placed in the deposition station SS, and the bag piece 220 (shown by a chain line) is attached to the rotary transfer device 86.
The actuators 210 are kept in a position where they do not grip or interfere with the bag pieces being fed and placed. As soon as one edge of the bag piece is properly abutted against the guide 194, one of the ends 218 having friction material is lowered to hold the bag piece in place. When the next bug piece is to be placed, the actuator that was actuated first retracts its end 218, and the other actuator descends to grip the previously placed bug piece and complete such action. is repeated. In some cases, the actuators may be actuated simultaneously. Once a predetermined number of bag pieces have accumulated in the stack, clamp 198 is actuated to retract actuator 204. The conveyor 92 is then indexed forward and the completed bag piece stack 220 is manually removed. Accurate registration of the deposit is maintained through the use of clamp 198.

Meanwhile, the bag making machine will be interrupted at a suitable number of cycles until the indexing movement of the conveyor is completed. A full cycle of the deposition operation is then resumed, and the clamp 198 is attached to the end 19 of the plate 192.
Separated from 6.

The bag pieces 220 are safely and accurately balanced on the stacking device 188, and the clamp 198 is provided to allow the bag pieces to be easily separated and formed into individual bags. A device capable of performing such an action can also be used in the first embodiment. The conditions for cutting and closing the web pieces are the same as in the first embodiment. If such a cutting operation is to be performed, it is desirable to provide each deposition device with a hollow deposition pin, or fence member, as indicated by reference numeral 222 in FIG.
Preferably, a heated rotary knife (not shown) is used to cut and optionally perform a cutting and sealing operation at the position indicated by reference number 222.

In the embodiment of FIG. 18, each deposition device 188 has two
opposite hinged side plates 22
6, which plate is adapted to be able to be raised after the cutting operation has taken place, thereby facilitating the removal of the finished pile of bag pieces. Actuation of the side plates can also be controlled by linear cams.

[Brief explanation of the drawing]

Figures 1A and 1B are side elevational views of the web processing machine when they are connected, and Figure 2 is a partially reduced side elevational view of Figure 1, but with different types of bags. A drawing showing a machine with a manufacturing mechanism,
3 is an enlarged perspective view of a cutting knife for removing a narrow strip of web from a tubular film; FIG. 4 is an enlarged perspective view of a gusset forming machine; and FIG. 5 is an enlarged perspective view of forming spaced apart perforations in a tubular web. An enlarged perspective view of the device; FIG. 6 is a perspective view of the punching device for punching holes in the central area of the web; FIG. and a perspective view of a sealing roll; FIG. 8 is a perspective view showing the placement of web pieces in a deposition device located at a deposition station; FIGS. FIG. 11 shows another embodiment of a transfer mechanism capable of transferring large web pieces in the lateral direction; FIG. 12 shows details of a second embodiment of the machine according to the invention. 13 is a plan view of the machine shown in Fig. 12, Fig. 14 is a partially enlarged view of the machine shown in Figs. 12 and 13, and Fig. 15 is a detailed view of Fig. 14. The plan view shown in FIG. 16 and FIG. 17 are along lines 21-21 in FIG.
The sectional view taken along the line 2-22 and FIG.
18 is a cross-sectional view similar to that shown in FIG. 17, but showing a modified version of the machine of FIG. 17; 28... Tension control mechanism, 58... Dancer device, 64... Tension roll, 76... Punch device, 66... Sealed cutting station, 86... Rotary transfer device, 88, 188... Deposition device, 102
... Cutting device, 120 ... Wheel, BS ... Bag piece, TS ... Transfer station, SS ... Deposition station.

Claims (1)

Claims: 1. A flat thermoplastic tubular film material is intermittently advanced along a path toward a hermetic cutting station 66, the material being hermetically cut sufficiently to separate the material into two bags. A method of manufacturing bags by forming web pieces of a predetermined size, the method comprising: carrying each formed web piece along a rotary transfer path 86 within the rotary transfer path;
pins 90 secured to the support blocks along the central region between the splittable bags so that the splittable bags hang downwardly over both sides of the support blocks; A bag manufacturing method characterized by holding the bag on top. 2. In the bag manufacturing method according to claim 1, a predetermined number of web pieces are deposited on the pin, and after the predetermined number of web pieces are deposited on the pin of the support block, the deposited web pieces are out of the rotary transfer path, and moving an empty support block into the rotary transfer path to begin depositing another web piece. 3. In the bag manufacturing method according to claim 2, the moved web pile is cut at a central region along the line between the pins and held by each pin on both sides of the support block. A method characterized by forming individual bag deposits. 4. The bag manufacturing method according to claim 3, wherein the knife 104 is heated before cutting the downwardly depending web piece pile in a vertical plane perpendicular to the central region of the web piece pile and in a vertical plane perpendicular to the central region of the web piece pile and in the direction of the pin. A method characterized in that the heating knife is moved downwardly at the center of the heating knife. 5. A bag manufacturing method according to claim 4, wherein the knife is heated to 93° to 105° C. in order to cut the stack of web pieces without welding adjacent web layers within each stacked bag. A method characterized by: 6. A method of making bags according to claim 4, in which said knife is used to weld adjacent web layers in each stacked bag to form two blocks of bags whose web layers are interconnected. 298
A method characterized by heating to ℃. 7. In the bag manufacturing method according to claim 1 or 2, before sealingly cutting one web piece, each material that has been advanced by a length corresponding to the web piece is
Pairs of two holes are provided and two pins of two pairs each are secured to the support grommet to hold the web piece approximately in place.
Closed cutting station 6 via 180° rotary transfer path
6 to a deposition station, and piercing the web pieces through holes in the web pieces onto respective pins 90 projecting upwardly from a deposition device 88 provided in the deposition station. 8. In the bag manufacturing method according to claim 7, two pairs of two
A method characterized in that a central strip of material 116 is removed from the layer of material before forming the holes. 9. A bag manufacturing method according to claim 7 or 8, wherein, before forming the holes, gussets defining a W-shaped bottom of the divisible bag are formed on both sides 132 of the material. A method characterized by: 10. A method of making bags according to claim 9, characterized in that, before forming the holes, parallel dotted lines 124 are formed in the central region of the material, spaced outwardly from the holes. . 11 The flat thermoplastic tubular film drawn from the feed web roll is sealed at cutting station 6.
6 and forming a web piece of a predetermined size sufficient to separate the bag into two bags, the apparatus comprising: A continuous conveying device 86 over supporting wood blocks 174 provided in the rotary transfer path transports the web pieces between the splittable bags so that the splittable bags hang downwardly over both sides of the support blocks. Apparatus for making bags, characterized in that the apparatus has a holding device 84 on pins 90 fixed to the support block along the central region of the bag. 12. The bag manufacturing apparatus according to claim 11, wherein the support block and a predetermined number of web pieces held on the block by the pins are moved out of the rotary transfer path, and another web piece is moved. A manufacturing apparatus characterized by a device 92 for moving an empty support block into the rotary transfer path to begin the deposition of the material. 13. The bag manufacturing apparatus according to claim 12, further comprising a device spaced apart from the rotary transfer path for receiving the moved support block and the web piece stack held by pins on the block. 100 and an apparatus 102 for cutting the web stack in half in a central region along the line between the pins to form two bag stacks held by respective pins on opposite sides of the support block. Manufacturing equipment featuring equipment. 14. In the bag manufacturing apparatus according to claim 13, a device 1 for moving the knife downward along a center line between the knife 104 and the pin.
06. A manufacturing device characterized by a cutting device having: 15. A bag manufacturing apparatus according to claim 14, wherein the knife is heated to a temperature between 93° and 105° C. in order to cut the stack of web pieces without welding adjacent web layers within each stacked bag. A manufacturing device characterized by having: 16. The bag manufacturing apparatus according to claim 14, in which two of the bags are bonded to each other by welding adjacent web layers in each stacked bag.
Cut the knife into approx.
A manufacturing device characterized by having a device for heating to 298°C. 17. In the bag manufacturing apparatus according to claim 11 or 12, each web piece has two
A manufacturing device characterized in that it is provided with a device 76 for drilling pairs of two holes 130, and an equal number of pins are secured to the support block and arranged to pass through the holes in the web piece. 18. The bag manufacturing apparatus according to claim 17, wherein each of the remaining layers of the web piece has two layers.
A manufacturing apparatus characterized in that it has a device 108 for removing a central strip of material 116 from one layer of the web piece before forming the pairs of two holes. 19. In the bag manufacturing apparatus according to claim 17, before forming the two pairs of two holes in the central region of the web piece, two parallel dotted lines 124 are drawn in the central region outside the holes. A manufacturing apparatus characterized by having a forming apparatus 52 spaced apart from each other. 20. The bag manufacturing apparatus according to any one of claims 1 to 19, further comprising a gusset defining a W-shaped bottom of the splittable bag before forming the hole in the web piece. A manufacturing apparatus characterized in that it has an apparatus 120 for forming on both sides 132 of the material.