POUCH MAKER

Abstract: A machine for making a pouch or bag package made from sealable plastics material comprises transport means (57, 58) for driving two mutually adjacent layers of plastics material to be sealed together, sealing means (53) at a first station for effecting sealing together of the two sheets along two spaced apart zones extending transversely of the direction of travel of the material during a pause in the forward direction of movement thereby forming two pouches, cooling means (56) located at a second station downstream of said first station, and means (70-80) for causing intermittent drive of said transport means whereby the two spaced apart sealed zones are conveyed from the first station to the second station where cooling takes place.

Description: POUCH MAKER This invention relates to a machine for making a pouch or bag package made from plastics material of the kind which can be closed by folding particularly but not solely 'for wrapping flake or ready rubbed tobacco. In a known pouch maker a length of plastics sheet is passed through a folder which folds the sheet along a line in the direction of transport and in such manner as to leave a flap for subsequent folding when the pouch has been filled. Heat sealing means effect sealing transversely of the direction of transport during intermittent pauses in the transport to form the sides of the pouch. Thereafter the folded and sealed sheet is severed along the line of sealing into individual pouches . For the purpose of sealing the plastics material an impulse sealing element in the form of a wire or strip was used. Between current impulses the wire or strip was rap dly cooled by water cooling means to give a permanent seal, both the sealing and cooling operation being effected at one and the same station. Rapid cooling is necessary to give permanence to the seal before transportation of the sealed sheet to the cutting station otherwise problems such as sticking of the softened plastic to transport rollers may occur and stretching at the seal. Due to the delay required for cooling immediately after sealing the speed of making the pouches is naturally limited and it is an object of the present invention to provide a machine in which the rate of production is dramatically increased. According to the invention there is provided a machine for making a bag package made from sealable plastics material- comprising transport means for driving two mutually adjacent layers of plastics material to be sealed together, means for causing intermittent drive of said transport means, sealing means at a first station for effecting sealing together of the two sheets along two spaced apart zones transversely of the direction of travel of the material during a pause in the forward direction of movement, cooling means located at a second station downstream of said first station, and means for causing intermittent drive of said transport means whereby the two spaced apart sealed zones are conveyed from the first station to the second station where cooling takes place. The mutually adjacent layers are preferably produced by folding a single sheet continuously along its length. Preferably the distance between the first and second stations is equal to one pouch length, considered in the direction of travel. However two pouches at each sealing operation could be formed ready for subsequent cooling and cutting. The invention will now be described by way of example with reference to the accompanying drawings in which:- FIGURE 1 is a side elevation of the pouch maker; FIGURE 2 is a side elevation with various portions of casing and parts omitted to show the path of the plastics material; FIGURE 3 is an end elevation as seen in the direction of arrow A in Figure 1 ; FIGURE 4 is a plan view of Figures 1 and 2 with the sealing and cooling heads removed, and FIGURE 5 shows a packaging machine including* the pouch maker of the present invention. Considered in the direction of travel of the sheet plastics material the pouch maker comprises a roll support 10 carrying by means of side plates 11, a spindle 12 bearing a roll of pre-printed plastics material 13 (e.g.. having a sheet thickness of 0.001mm). Extending from the side plates 11 are a pair of arms 14 having rotatably mounted between them two guide rollers 15, 16. A further guide roller 17 is mounted between the upper ends of the side plates 11 adjacent which roller 17 is provided an adjustable tensioning device 18. Attached to the extensions 19 of the edges of the plates 11 are a pair of guide channels 20 along which the bearing ends of a first buffer roller 21 can travel. The roller 21 maintains a tension on the plastics sheet P by reason of its weight and can move vertically to accommodate variations in the rate of demand. Mounted on a framework 22 at the upper end of upstanding ' ' pillars 23 is a folder 24 comprising smooth metal sheets inclined to each other. The folder 24 is pivotally mounted at its upper end on bearings coaxial with a guide roller 25 and held at its lower end by a turn-screw 26. A further guide roller 27 is mounted on the framework 22 substantially vertically above the buffer roller 21 and between the latter and the guide roller 25. Beneath the folder 24 i * s prov ' ided ' a pair of idler pinch rolls 28 carried between the pillars 23- These pinch rolls 28 are disposed on axes set at right angles to the axes of the rollers 15, 16, 17, 21, 27 and 25 and receive the folded plastics sheet as it leaves the folder. Rollers 17 and 18 are nip rolls driven by an electric motor (not shown) . This unwinds the plastic sheet from the preprinted plastic roll 13. The motor is switched on and off by limit switches (not shown) situated at the upper and lower travel of the buffer roller 21. To draw the sheet and over the folder 24 there is provided a pair of driven pinch rollers 30 having journals mounted in bearing blocks 31 bolted to horizontal' channel members 32 carried at one end by the pillars 23 and at the other end on legs 33- The speed of the pinch rollers may be varied according with demand. A second buffer roller 34 is provided having its ends freely guided in channels 35 attached vertically to the two horizontal members 32. Two guide rollers 36, 37 are mounted one on either side of a vertical plane containing the axis of the buffer roller 34 on short upright αeπbers 38, 39 attached to the horizontal members 32. Two other guide rollers 40 and 41 are disposed on mountings 42, -3 attached to the horizontal members 3 at a height level with guide rollers 36, 37 and the region of pinch of : the rollers " 30. The arrangement thus so far described serves to draw the material from the roll to fold it over to leave an overlapping margin to serve as the pouch lap, and deliver the folded material in horizontal disposition ready for sealing whilst maintaining the drawn off sheet and the folded sheet in tension to ensure no wrinkles or creases. A sealing and coolir.g portion of the machine is shown generally at 50 and comprises a sealing station in the form of a compartment 51 having a platen 52 above which a double element sealing member 53 is provided. The sealing member 53 which is maintained' permanently hot at a temperature compatible with the material and thickness is supported and reciprocated by mechanism not shown. The double element sealing member 53 is coated with a non stick material such as PTFE (Teflon, Registered Trade Mark). Adjacent the sealing compartment 51 is a cooling compartment 55 having a water-cooled plate 56 which reciprocates vertically by the same mechanism (not shown) which supports and reciprocates the double element sealing members, over a fixed platen 56a. The plate 56 and platen 56a may be made of aluminium. The sheet is drawn through the sealing and cooling portion 50 by two pairs of pinch rolls 57, 58. ' The pinch rolls on each side of the compartments 51 , 55 are driven intermittently and in synchronism by drive mechanism to be described later. A cutter 60 is provided at the outlet of pinch rolls 59- Since the sheet is sealed in the compartment 51 to form two pouches at a time and cutting of the pouches takes place singly an accumulator region is provided which comprises three weighting rollers 61, 62, 63 mounted at their ends in yokes 64 which are guided by vertical channels 65. Guide rollers 66, 67, 68 are disposed at the level of the pinch rollers 58, 59 and form part of the accumulator region. The pinch rolls 57, 58 and 59 are driven from a motor 70 and the main pouch packer motor (not shown) respectively by chains and sprockets (not shown) and cranks 71,- 72. The crank 71 has a rod 73 pivotally attached thereto which by a rack 74 drives a pinion 75 mounted on the spindle end of the lower of the two pinch rolls 57- A one way clutch (not shown) is provided at the spindle end so that the pinch rolls only rotate in a direction to feed the sheet forwards. Likewise the crank 72 -has a rod 78 having a rack 79 in driving engagement with a pinion 80 by which through a one way clutch (not shown) the lower of the two pinch rolls 59 is driven. Chains and sprockets (not shown) drivably connect the lower of eadh of the two sets of pinch rolls 57, 58 so that the pairs of pinch rolls move in synchronism. Since the sealing takes place in-pairs of pouches and cutting takes place singly it is necessary to arrange that the pinch rolls 59 feed intermittently at twice the rate of feed of the pinch rolls 57, 58. A photocell 90 is provided to detect a registration mark such as a white printed portion, of each pouch. However, a control circuit receiving pulses in accordance with the detected white portions is arranged to initiate advance of the sheet after detecting every other pouch. The sheet after sealing along two lines is moved the equivalent of two pouches width from the sealing position and cooling by the descending plate 56 then takes place. The cutter 60 is controlled in accordance with demand by feedback from the subsequent transfer unit e.g., of the kind described in Patent Application No. (Case A) filed simultaneously herewith. A second photocell (not shown) situated just before pinch rolls 59 is provided to detect a registration mark, such as a white printed portion, of each pouch. This ensures that one pouch at a time is ejected from the pouch maker through the cutter 60. The accumulator is provided with a limit switch 82 which controls the supply of pouches being produced by the pouch maker. When limit switch 82 is closed, a signal is sent to the control system to stop producing pouches. In this event the pouches which have been heat " sealed under the sealing elements 53 are indexed to be under the water cooled plate 56 whereupon the- water cooled plate 56 is activated by a pneumatically operated over-ride system. This enables that sealed pouches are not left to cool slowly and so distort. By producing two sealing zones and after a suitable pause shifting these sealing zones to the cooling compartment it is possible to increase the speed of production to' a speed about twice that of known machines . The above described pouch maker is incorporated in the tobacco packaging machine shown in plan in Figure 5 which comprises a pouch packer turret assembly 101 to which is -supplied portions of weighed tobacco from a 25g hand rolled tobacco (HRT) weigher 102 via a bucket conveyor 103 and empty pouches from the pouch maker 104 via a pouch transfer unit 105. After filling the pouches are taken from the turret assembly 101 by a take-off device 106 and transferred to a pouch folder 107. The folded pouches leaving the folder are deposited on a conveyor 108 which conveys the pouches to a labelling unit 109- The remainder of the packaging line includes a take-off conveyor 110, a check weigher 111, a buffer store 112, a doffer 13, a pouch replacement device 14. an over-wrapper 115 and a boxing unit 116. The overall packaging .machine fortns the subject of Patent Application No. (Case A). One of the most important and distinctive aspects of the pouch maker is what happens when the machine is stopped. In such an event, the polythene is indexed from the heated dies to the water cooled dies and the water cooled dies activated by means of a pneumatically operated over ride system without heat sealing the next pair of pouches. In normal operation, the hot and cold dies, which are attached to a common can operated yoke arrangement, would act in unison. This sequence of stopping ensures that deformed heat seals are not obtained.

Claims: CLAIMS : 1. A machine for making a pouch or bag package made from sealable plastics material comprising a) transport means for driving two mutually adjacent layers of plastics material to be sealed together, b) sealing means at a first station for effecting sealing together of the two sheets along two spaced apart zones extending transversely of the direction of travel of the material during a pause in the forward direction of movement thereby forming two pouches, c) cooling means located at a' second station downstream of said first station, and d) means for causing "intermittent drive of said transport means whereby the two spaced apart sealed zones are conveyed from the first station to the second station where cooling takes place. 2. A machine as claimed in claim 1, wherein said sealing means comprises a compartment containing a platen above which reciprocates a double element sealing member, and said cooling means comprises a compartment having a platen above which reciprocates a cooling plate. ^ 3- A machine as claimed in claim 2, wherein the ' cooling plate is water-cooled . 4. A ' machine as claimed in claim 2 or 3, wherein the two platens are coated with a release material. 5. A machine as claimed in claim 2, 3 or 4, wherein a first pair of pinch rolls is provided at the sheet entry side of the sealing compartment, a second pair of pinch ' rolls is provided at the exit side of the cooling compartment, and first driving means for driving said first and second pairs of pinch rolls in synchronism including crank mechanism and one-way clutches by which the sheet is advanced from the sealing station to the cooling station. 6. A machine as claimed in claim 5, wherein a cutting mechanism is provided and second driving means * ___ therefor, said second driving means being controlled in timed relationship with the first driving means and operated at twice the rate of said first driving means. 7. A machine as claimed in claim 6, including an accumulator disposed between the cutting mechanism and the pinch roles at the exit of the cooling compartment, said accumulator comprising a plurality of guide rollers on fixed horizontal axes and a plurality of weighting rollers disposed horizontally, said weighting rollers serving to take up the variable loop of material being fed to the cutting mechanism.

Inventors: ESCH FRIEDRICH DIETER, PRICE JOHN GERYN, ESCH, FRIEDRICH, DIETER, PRICE, JOHN, GERYN
Applicants: AMF INC, AMF INCORPORATED
Application year: 1985
Main classification: B31B23
IPC codes: B65B1, B65B7, B65B43