WO2006010732A1

WO2006010732A1 - Method and machine for fabricating paper shopping bags

Info

Publication number: WO2006010732A1
Application number: PCT/EP2005/053531
Authority: WO
Inventors: Franco Barilli
Original assignee: BL Macchine Automatiche SpA
Current assignee: BL Macchine Automatiche SpA
Priority date: 2004-07-27
Filing date: 2005-07-20
Publication date: 2006-02-02
Anticipated expiration: 2007-01-27
Also published as: ITBO20040473A1

Abstract

The sheet for forming the bag is taken from a reel or from a stack, is orientated with the printing downwards, and is subjected to a first horizontal translation during which it is provided with lines of adhesive for the application of the paper pieces to reinforce the upper edges of the future larger lateral walls of the bag, these pieces being applied to the sheet at the end of this first translation movement. The edge of the sheet with the said reinforcing paper pieces is folded in a book-like way if necessary and the sheet is pulled by this edge and is translated to the bag forming station, while the line of adhesive is applied to one of the sides parallel to the direction of movement for the future tube-like closure of the sheet which is carried out by suitable folders and by an upper presser, on a forming block carried with other forming blocks by a carousel with a vertical axis, after the paper piece for reinforcing the bottom of the future bag has been fed to the vertical wall of this forming block. By cyclic movements, the carousel transfers the tubular article to successive stations for closing the bottom flaps, with the application of lines of adhesive, to a station for pressing these folded and glued flaps, and finally to a removal station where means operate to remove the bag and simultaneously flatten it and make at least a pair of holes in its reinforced edge for the future fitting of the handles. The bag can be collected and sent to a manual cycle for fitting the handles, or can be fed to one of the gripping means of a second carousel with a vertical axis, which holds the bags by their bottoms and externally by their lateral walls and which positions the bags in succession at corresponding stations in which the handles, of cord for example, are fitted into the appropriate holes in the open mouth of each bag, and in which the handles are knotted, for example, on their ends inside the bag and in which the bag with its handle is re-flattened and discharged.

Description

TITLE:

"Method and machine for fabricating paper shopping bags"

DESCRIPTION

The invention relates to a method and the corresponding machine for the automatic fabrication of shopping bags, made from paper and/or any other suitable material, having the same quality characteristics as those currently made by hand. The machine in question has an estimated output of approximately 12,000 bags in one eight-hour shift, for which the presence of two or three persons is required on average. Considering that, in the present manual production cycle, approximately 6500-7000 bags are produced in an eight-hour shift, requiring approximately twenty operatives, the technical progress provided in this field by the machine according to the invention can easily be appreciated. The machine operates in a fully automatic way, picking up a sheet of paper from a stack or a reel, placing it on a horizontal plane and translating it in the direction of the largest dimension, while suitable means form lines or spots of adhesive a short distance apart and parallel to the side of the sheet on which, at the end of the translational movement, other means apply the reinforcing paper pieces for the future larger and upper sides of the bag, where the handle will be fitted (see below). During the said translation step, the rear corner area of the side on which the adhesive is applied is chamfered by a cutting operation, while holes are made in the front corner area of the same side, for reasons described below. The side of the sheet to which the said reinforcing paper pieces have been applied is folded by suitable means, in such a way that the said paper pieces are placed inside the folded portion and are therefore invisible. By means of a gripper which acts on the folded side of the sheet, the sheet is translated horizontally in a direction which is at an angle of 90° to that of the preceding translation, and in this step the sheet is positioned under a parallelepipedal forming block of a carousel with a vertical axis, which carries another three identical forming blocks which are spaced apart from each other at equal angular intervals, this carousel being rotated on command, always in the same direction, through ninety degrees each time. During the second translation step, the sheet is provided with at least one line of adhesive of the side which is parallel to the direction of movement and which terminates at its leading edge in the chamfered corner area, which has the function of bringing the line of adhesive as close as possible to the front side of the sheet which is to be folded and internally reinforced by the paper pieces. At the end of the second translation step, the sheet is positioned, as stated previously, under one of the said parallelepipedal forming blocks of the carousel, whose base facing the direction of feed of the sheet carries suction means which retain a rectangular piece of paper fed to it at the correct time by suitable means, this piece of paper having the function of reinforcing the bottom of the future bag. Under the sheet which arrives under the said forming block, there are provided folding and scoring means which, at the correct time, after the sheet has been released by the translation grippers, raise the sheet against the said forming block and wrap it in such a way as to form a tube, with the upper flaps overlapping and fixed to each other by the line of adhesive provided in the aforesaid second translation step. The adhesive which is located on the chamfered and folded edge of the sheet is superimposed on the area with the holes in the opposite edge, in such a way that the adhesive passes through to the lower layer of the folded portions and firmly fixes the parts even in these portions consisting of a plurality of superimposed layers. The folding of the upper edges and their overlapping on each other, on the upper wall of the stamp, are completed by a presser which forms a Y-shaped score on the upper side of the tube, while a corresponding Y-shaped score is formed on the lower side of the tube, by means of a lower component of the said folding means, also making use of a suitable arrangement of the lower and upper horizontal walls of the forming block for this purpose. The aforesaid Y-shaped score has the function of preparing the future smaller and frontal walls of the bag for accordion-folding. In the next step, after the fixing adhesive of the tube has set, the said folding means return to the lower rest position, the upper forming block rises and the carousel rotates through ninety degrees, positioning a new forming block next to the said folding means, for repeating another cycle as described, while the forming block, wrapped by the tube and with the bottom paper piece, moves to a second station where means are provided to fold the short flaps vertically on to the paper piece, these short flaps being the upper ones below the horizontal articulation of the part of the tube which projects from the forming block, then to distribute first vertical lines of adhesive over the set of the said first flaps and the visible part of the bottom paper piece, then to fold on to these one of the larger bottom flaps of the tube, with a vertical articulation, then to distribute further lines of adhesive on this flap and on the bottom paper piece, and finally to fold on to these the other larger flap of the tube. In the next step, the carousel rotates through a further ninety degrees and the forming block with the bag is transferred to a third station, where a presser acts on the bottom flaps until the said lines of adhesive have set, while suitable guide means keep the said flaps in the closed position during the movement from the second to the third station. In the next step, the carousel rotates through a further ninety degrees and transfers the forming block with the bag, closed at its sides and at its bottom, to a fourth station where means positioned at the edge of the forming block decrease its cross section in such a way that the bag can be removed from the forming block by suitable means, while the inflated parts of the bag are flattened and its bottom is rotated through ninety degrees on the said flattened part, and in these conditions the bag is inserted between a pair of parallel conveyors with a vertical axis, which flatten the bag and hold it correctly on edge when cutting means located upstream of the conveyors come into action to form, in the temporarily stationary bag, through-holes for the future fitting of the handle, usually made from cord, and any necessary holes for the fitting of any necessary improvised closure. On leaving the said conveyors, the bag can be collected in stacks and sent to a manual cycle for fitting the handle, or, in a more complete version of the machine, the bag can be fed to one of the pick-up means of a second carousel with a vertical axis, which holds the bag by the bottom and by the side walls and which, by cyclic rotations, positions the bag in successive stations where the cord handles are fitted into the appropriate holes in the reinforced open sides of the open mouth of each bag, the said handles being knotted on their ends inside the bag and the bag with the handle being re-flattened and placed on a conveyor which removes it and causes it to interact with a parallel smoothing conveyor lying above it, which returns the bag to the original flat condition for stacking.

Further characteristics of the machine in question and of the corresponding operating method, and the advantages obtained therefrom, will be made clearer by the following description of a preferred embodiment of the machine, illustrated purely by way of example and without restrictive intent in the figures of the twelve attached sheets of drawing, in which:

Fig. 1 is a schematic perspective view of the principal devices which make up the machine, in the version in which the paper sheets are fed from a stack, and without the handle fitting means;

Fig. 2 is a perspective view of the initial station of the machine, in the version in which the sheets of paper are drawn from a reel;

Fig. 3 is a schematic perspective view of the devices which can be added in series with the machine of Figure 1 , for automatically fitting the handles to the bags; - Fig. 4 is a lateral elevation of the means for feeding paper sheets picked up from a stack to the subsequent first translation means;

Fig. 5 is a view from above of the means of Figure 4 and of the subsequent means for the second translation of the paper sheets;

Fig. 6 is a schematic view from above of the carousel with a vertical axis with the bag forming blocks, shown in relation to the said means for the second translation of the paper sheets, and with some of the corresponding operating stations;

Fig. 7 is a schematic lateral elevation of the means for feeding the paper pieces for reinforcing the upper edges of the lateral walls of the future bag and for feeding the paper piece for reinforcing the bottom of the bag to the forming blocks of the carousel of Figure 6;

Figs 8 and 8a are schematic side views, in partial section, of the means for folding the side of the sheet which is provided with the paper pieces for stiffening the upper edges of the lateral parts of the future bag, these means being shown in subsequent stages of their operating cycle; Fig. 9 is a side view of the first operating station of the carousel of Figure 6, this station being responsible for making the paper into a tube on a forming block of the carousel;

Figs 10 and 10a are front views of the station of Figure 9, shown in successive stages of its operating cycle;

Figs 1 1 , 11 a and 1 1 b show in plan from above, and in successive operating stages, the final station for discharging the shaped bags from the carousel of Figure 6;

Figs 12, 13, 14, 15, 16, 17, 18, 19, 20 and 21 are perspective views of the bag and some components of the machine, during the same number of stages of the bag formation cycle;

Fig. 22 is a plan view of a variant embodiment of the initial part of the machine in the version in which the sheets are fed from a pair of adjacent stacks, for forming large-format bags; - Fig. 23 shows details viewed through the cross section line XXIII-XXIII of Figure 22;

Figs 24, 25, 26 and 27 show in lateral elevation the means of the station of Figure 23 in successive stages of their operating cycle;

Fig. 28 is an end-on sectional view of the tubular article for forming the bag, produced by the means shown in Figures 22 to 27.

As shown in Figures 1 and 2, the machine comprises a first station A for automatically feeding a rectangular sheet F of paper and/or other suitable material, having dimensions such that a bag can be formed from it, to a horizontal conveyor 1 formed by perforated parallel belts, the upper branch of which runs over fixed manifolds 2 connected to a suction source (see below). On the conveyor 1 , the sheet has to be turned so that the printed surface faces downwards and the larger dimension is orientated in the longitudinal direction of the conveyor in question. The conveyor 1 is driven by a motor with electronic speed and phase control, by the procedures described below. The sheets F can, for example, be drawn from a reel 3 positioned laterally with respect to the conveyor 1 and parallel to it, as shown in Figure 2. The strip of paper unwound from the reel 3 is taken in a zigzag path around a set of parallel rollers 4 which have the function of buffering and smoothing the strip, to remove the curvature acquired when it was wound on to the reel, and then to return it to the flat form, after which the strip is drawn by a pair of parallel motorized rollers 5 and is carried transversely by suitable means on to a supporting surface (see below) and on to the initial part of the conveyor 1 which is temporarily stationary, while at the correct time suitable means, indicated schematically by the arrow 6, make a transverse cut to separate the sheet F, located on the said conveyor 1 , from the strip. Suitable means (not shown) are provided to align the sheet F against a fixed reference 7 positioned in a parallel way on the side of the conveyor 1 opposite the side facing the reel 3.

In a different embodiment, which was first produced by the applicant, in the station A the sheets F can be stacked with the printed surface upwards and a palletized stack 8 of these sheets is positioned laterally by the initial part of the aforesaid conveyor 1 and, as also shown in the details of Figures 4 and 5, the stack is positioned on an elevator 9 and has one of its walls bearing against at least one vertical fixed reference wall 10, the said elevator being fixed to a support structure 1 1 which is, for example, U-shaped in plan and whose sides carry sliding blocks 12 which slide on vertical guides 13 fixed to a support frame 14, microswitches 15 and 15' being provided to signal the low position and the position of maximum raising of the elevator respectively. The sides of the structure 1 1 are fixed to the ends of corresponding closed chains 16, the ends of whose vertical portions run round sprockets 17 and 18 located respectively in the lower and upper part of the said frame 14, the ends of the horizontal portions of these chains running round sprockets 19 keyed on a timing shaft 20 supported rotatably by a base structure 21 and driven by a power unit (not shown), with an electric motor having two directions of rotation and preferably of the type with electronic speed and phase control, which automatically causes the cyclic raising of the elevator 9, so that the top of the stack of sheets 8 is always correctly positioned next to level sensors 22 and next to a bar with suction cups 23, held by pairs of composite articulated parallelogram structures 24 pivoted at 25 on the frame 21 and made to oscillate by suitable cams 26 keyed on a shaft 27 which is rotated at the correct speed by a power unit (not shown). On the same shaft there are also keyed cams which are connected to a mechanical safety feeler 28 which acts on the top of the stack 8, as in known equipment for automatically feeding sheets to a printing machine, on which equipment the station in question is clearly based. This feeding station is distinguished from the known art in that the sheet picked up and translated by the bar with the suction cups 23 is positioned by the latter in the initial part of an adjacent conveyor with parallel perforated belts 29 which run on manifolds 30 in the form of a U rotated through ninety degrees, with a portion having a large radius of curvature opposite the stack 8 and divided into sectors which can be driven selectively by suitable means, the belts running outside these manifolds, on shafts 31 parallel to the longitudinal axis of the underlying conveyor 1 , one of these shafts being connected to the chain 32 which takes its motion from a sprocket keyed to the shaft 27 of the cams and which is driven by the power unit 33. The vacuum pump connected to the said manifolds 30, and to other suction means described below, is not shown in the drawings and is driven by its own motor. The paper sheet F fed by the suction cups 23 is collected by the conveyor belts 29 which complete its withdrawal from the top of the stack 8 and carry it in a tilting path above the initial part of the conveyor 1 and an adjacent support surface 1 12, in the form of a comb, in such a way that the printed surface of the sheet, which previously faced upwards, finally faces downwards. When the sheet F reaches a position above the conveyor 1 and the surface 1 12, suitable means neutralize the lower sectors of the manifolds 30 and the sheet F falls from the belts 29 and its front edge, with respect to the direction of movement, touches the vertical teeth of a comb 34 which holds it correctly on the surface 1 12 and on the initial part of the conveyor 1 which is temporarily stationary. The teeth of the comb 34 engage in lateral apertures 35 of the surface 1 12, visible in Figure 5. The teeth of the comb 34 extend from above and are associated with a sliding block, which moves on guides 36 positioned in a parallel way between the lower sectors of the manifolds 30, and which, by means of suitable levers, derives its motion, for example, from at least one cam keyed on the shaft 27. When so commanded, the teeth 34 of the comb cause the sheet to be translated on the surface 1 12 and on the conveyor 1 , so as to bring the opposite edge of the sheet to bear on a fixed reference 7 located on the side of the surface 1 12 and of the conveyor 1 opposite the side facing the stack 8. In the next step, means are provided to activate the suction manifolds 2 associated with the belts of the conveyor 1 , to fix the sheet to the latter, and means cause the activation of this conveyor, initially at a slow speed, and, when the front edge of the sheet F is detected by optoelectronic means 37 (Fig. 5), suitable means cause the conveyor to advance at a suitable speed to transfer the sheet, centred in a predetermined way according to the format, to the subsequent station B. During the translation from station A to station B, the sheet F is temporarily halted, firstly at a station 38 which forms in the sheet a correct number of holes 39 parallel to and a short distance from the front edge with respect to the direction of movement of the sheet, and secondly at a station 40 which makes a diagonal chamfering cut 41 in the corner area of the rear side of the sheet F, opposite the portion of the sheet in which the said holes 39 are formed (see below). During the translation from station A to station B, at a short and exact distance from the said longitudinal side of the sheet on which the chamfer 41 is formed, suitable stationary means 42 dispense lines of adhesive 43, 43' which, when the sheet F halts at the station B, are suitably centred with respect to magazines 44, 44' which contain the paper pieces 45, 45' for reinforcing the future upper edge of the bag (see below), and these paper pieces are picked up by means 46 with suction cups from the said magazines and are applied to the portions of the sheet F with the said lines of adhesive, as shown in Figures 5 and 7, so as to be fixed firmly to the sheet. Figure 7 shows how the means 46 oscillate on a pivot 47 and are driven, by means of levers, by cams 48 keyed on a secondary drive shaft 49 parallel to the return shafts of the conveyor 1. Clearly, in some possible variant embodiments, the lines of adhesive 43, 43' and the reinforcing paper pieces 45, 45' can be applied to a more inward portion of the sheet, spaced apart from the edge of the sheet by a distance substantially equal to the width of the said paper pieces. In another variant, two parallel adjacent pairs of paper pieces 45, 45' can be fixed to the sheet F, and can then be overlapped on each other after the folding step, described below, which forms the future reinforced upper edge of the bag.

Figures 7 and 8 show how the side of the sheet to which the reinforcing paper pieces 45, 45' are applied rests on a folder 50 which initially opposes the said application means 46 and which is supported by rotation means (not shown) which, on command, make it rotate through 180° in the anticlockwise direction according to Figure 8, by rotation about its longitudinal edge 50'. A blade 51 , which was previously, for example, in a raised position, and which acts as an opposing piece in the step of folding the sheet, has its front edge positioned on the sheet F at the correct time, at the edge 50' of the folder 50 and parallel to the latter. The portion of the sheet folded by the folder 50, which in the present example is provided with the reinforcing paper pieces 45, 45', is turned over on to this blade. The blade 51 is connected to means (not shown) which, after the active movement of the folder 50, translate the blade away from the folder and from the conveyor 1 , as shown in Figure 8a, so as to insert the folded portion of the sheet, reinforced by the paper pieces, between a pair of grippers 52, 52' which have been brought up to the folder at the correct time and which are then closed to grip the folded portion of the sheet, while the said blade 51 is withdrawn to the rest position at the correct time. Figure 8 shows how suitable pressers 150 are provided to hold the sheet temporarily on supports 250 positioned between the belts of the conveyor 1 , when the sheet reaches the station B, so as to prevent any undesired movement of the sheet during the active step of upward rotation of the folder 50. The blade 51 is characterized by a comb shape, to allow the passage of the pressers 150. Clearly, the scope of the invention also includes the variant in which the means of Figure 8 and the folding step performed by them are not used, for the fabrication of bags with their upper edges reinforced by the inner paper pieces 45, 45' but not folded, or folded in a subsequent step, after the creation of the tubular article for forming the bags (see below).

The grippers 52, 52' have the function of transferring the paper sheet F from the aforesaid station B, in which the reinforcing paper pieces 45, 45' are applied, to a subsequent station C which is considered below, and in this step stationary means 53 dispense at least one line of adhesive 54 on to the side of the paper which is provided with the chamfered corner 41 and which is parallel to the direction of movement, this line of adhesive extending over the whole length of the sheet because of the said chamfer, even under the portion which has been edged and reinforced with the said paper pieces. At the end of the active translation path, the grippers 52, 52' correctly position the sheet F, with the printed surface facing downwards, under one of the parallelepipedal forming blocks 55 of the station C, which form a positive model of a bag, as also shown schematically in Figure 12 which illustrates the bag forming process. The number of forming blocks 55 is four, for example, and they are positioned at equal angular intervals on, and project from, a carousel with a vertical axis 56, which is rotated by suitable means (not shown) in steps of ninety degrees, for example in the clockwise direction with respect to Figure 6. The details of Figures 6 and 9 show that the parallelepipedal forming blocks 55 are positioned on edge, with the smaller lateral walls at the top and bottom and in horizontal positions. The larger vertical lateral walls, and the smaller upper lateral wall and the front vertical wall, are fixed, while the smaller lower lateral wall of each forming block is fixed on sliding blocks 57 which slide on diagonal slides 58 and which are connected to a linear actuator 59 which, on command, can raise or lower the sliding block 57 together with the lower wall in the directions indicated by the arrows 60 in Figure 9. When the lower movable lateral wall of the forming block is in the low position, it completes a lower portion of the other three adjacent walls of the forming block, and therefore, when this movable wall is raised, the height of the forming block is suitably decreased. This characteristic is used to facilitate the removal of the bag from the forming block at the end of the forming cycle (see below). In the active operating step of the forming block 55, its lower lateral wall is in the low position.

The vertical bottom wall of each forming block 55 is provided with suction cups 61 (see also Figure 13) which are activated to retain the paper piece 62 for reinforcing the bottom of the future bag. This paper piece is drawn from a magazine 63 positioned between the magazines 44 and 44' (Figs 5 and 7), by a parallelepipedal suction manipulator 64, which, after having transferred the paper piece to the forming block 55, remains temporarily in association with the forming block to complete in a coplanar way the horizontal extension of the four lateral walls of the block. The manipulator 64 therefore has the same vertical section as the forming blocks 55 of station C. Figures 7 and 9 show how the manipulator 64 is hinged at 65 on an arm 66 which, in order to interact alternately with the magazine 63 and with the forming block 55, is oscillated on a pivot 67 by first and second levers 68 and 68', and by at least one cam 69 keyed on the secondary drive shaft 49. On the shaft 65 which is fixed to the manipulator 64, there is keyed a sprocket 70 which is connected by a chain 71 to a sprocket 72 rotatable on the pivot 67 and connected to first and second levers 73 and 73' which follow the profile of a cam 74 keyed on the said drive shaft 49. By the action of these means, the manipulator 64, while oscillating on the arm 66, is rotated around the shaft 70 so that its face on which the suction and pick-up means open is positioned initially parallel to the bottom of the magazine 63, in order to pick up a paper piece from it, and then parallel to the vertical wall of the forming block 55, to position and transfer the said paper piece on to the pick-up means 61 provided on this wall of the forming block.

In the location C1 of the station C, the sheet is correctly positioned by the electronic means which control the motor for advancing the grippers 52, 52', and, at the end of the active travel of these grippers, the sheet is secured by lower suction cups 75, so that it is positioned with a precise reference with respect to the forming block 55 located above it. At the correct time, the grippers open and move away, and the sheet F is left on folding means which will now be described with reference to Figures 9 and 10 and which comprise a central horizontal part 76, opposite and complementary to the lower lateral wall of the forming block 55 located above, and freely hinged in a book-like way at 77 and 77' to flaps 78 and 78' which are complementary to the vertical lateral walls of the forming block 55 and which have short folding plates 80 and 80' hinged on their outermost sides at 79 and 79', the plates 80 and 80' being connected to pneumatic actuators 81 , 81 ' whose rods are initially retracted. At the start of each cycle, the central part 76 is in the low position shown in solid lines in Figure 9 and in broken lines in Figure 10, and the flaps 78, 78' are in a horizontal position coplanar with the part 76, which is mounted on a sliding block 82 which can slide on a vertical guide 83 and which can be raised and lowered on command by means of levers 84 and a cam keyed on a secondary shaft 49'. Further cams, which activate first and second levers 85, 85' hinged at 86, 86' to corresponding arms 87, 87' fixed to the said flaps 78, 78', are mounted on the secondary shaft 49' and on the parallel shaft 49, these shafts being synchronized with each other. The sequence shown in Figures 10a and 10 and in the process diagram 14 clearly show how, after the raising of the central part 76 of the folding system, the sheet is pressed by this part against the lower lateral wall of the forming block 55 located above (see below), and how, at the correct time, the flaps 78, 78' are rotated upwards, through ninety degrees, to fold corresponding portions of the sheet against the vertical lateral walls of the forming block 55. When the flaps 78, 78' have been raised, as also shown in the process diagrams 15 and 16, the cylinders 81 , 81 ' are operated to fold the final portions of the sheet through a small distance on to the upper wall of the forming block, so that the larger of these portions, which has the line of adhesive 54 (Figs 5 and 6), is placed on top of the other portion, after which a presser 88, operated by a stationary vertical actuator 88', is activated at the correct time to press the said final portions of the sheet on to the upper wall of the forming block, thus fixing these portions of the sheet firmly together and completing the formation of the paper tube around the forming block 55 and around the manipulator 64 temporarily associated with the forming block. The said smaller upper portion of the sheet is mostly overlapped by the larger upper portion, so that the joint line between these two portions of the sheet appears close to a corner area of the forming block 55. Figures 15 and 16 show how, because of the presence of the said holes 39 and the corner chamfer 41 , the line of adhesive 54 acts at a certain depth, thus also firmly fixing together the folded reinforced portions of the tubular paper article formed on the forming block 55. In this step, as a result of a suitable configuration of the forming block 55 and of the manipulator 64 and of the said folding means 76, 78, 78', 80, 80', the paper tube wrapped around the forming block 55 and the manipulator 64, is provided with sufficiently deep scored lines on the horizontal corner edges of the assembly 55, 64, so that when the paper article is subsequently removed from the forming block (see below) the article remains in its rectangular parallelepipedal shape. During the folding step which has been described, as a result of a suitable configuration of the intermediate part 76 of the folders and of the upper presser, and as a result of a suitable configuration of the lower and upper horizontal walls of the forming block 55 and a suitable configuration of the presser 88, the corresponding lower and upper horizontal walls of the tubular paper article wrapped around the forming block are provided with sufficiently deep scored lines 89, in the form of a letter Y, as shown in Figure 6, running along the midlines of the said walls and joining in the corner areas of the bottom of the future bag, to impart the necessary capacity of accordion folding to the lateral walls of the bag (see below). When the line of adhesive 54 has set, the presser 88 is raised, and all the lateral folding means shown in Figure 10 are lowered to the rest position, and the manipulator 64 shown in Figure 9 is inactivated and drawn horizontally out of the article, while the bottom paper piece 62 remains attached to the suction means 61 of the forming block 55, and in the next step the carousel 56 of the station C rotates through ninety degrees to transfer the forming block with the tubular paper article into the location C2, while a new forming block enters the location C1 to repeat the described cycle. Means which will now be described with reference to Figure 6 and the process figures 17 to 21 operate at the location C2. Folders 90, operated by rectilinear vertical or oscillating actuators, not shown in detail in the drawings since they can easily be produced in various forms by persons skilled in the art, fold the horizontally hinged upper and lower flaps L1 , L2 of the portion of tube projecting from the forming block 55 on to the bottom paper piece 62, and at the end of the cycle these folders leave an ample portion of the folded flaps free. In the next step, a group of three guns 91 is made to travel vertically downwards, only two of these guns, namely the central gun and one outer gun, being active, so as to dispense corresponding lines of adhesive 92 on the midline, and at a small distance from the midline, of the bottom paper piece 62 and of the free portions of the said folded flaps L1 , L2. In the next step, as shown in Figure 19, a folder 93 (Fig. 6) folds the vertical flap L3 which is fixed on the said lines of adhesive 92 and which at the end of the step is left sufficiently free by the said folder, so that after the upward return of the said guns 91 (Fig. 20) the guns are activated to dispense two lines of adhesive 94 on to the previously folded flap L3 and to the side of it, so that the adhesive is applied to the bottom paper piece 62 and the flaps L1 , L2. After the upward travel of the guns

91 has ceased, a folder 95 (Fig. 6) comes into action to fold the vertically hinged final flap L4 on to the flap L3, as also shown in Figure 21. The folders 90 have been retracted at the correct time into the rest position and, while the folders 93 and 95 remain temporarily in the active position, the carousel 56 rotates through 90° to transfer the forming block with the bag closed at its bottom from the location C2 to the subsequent location C3, while a fixed curved guide 96 keeps the bottom flaps L1 - L4 in the closed position, and when the forming block reaches the location C3 a presser 97 comes into operation to exert a uniformly distributed pressure on the bottom of the bag and of the forming block 55, for the time required to ensure the fixing of the said flaps and the bottom paper piece by the aforesaid lines of adhesive

92 and 94. In the next step, the presser 97 is inactivated, and a rotation of the carousel of station C through 90° causes the forming block, with the bag closed at its bottom, to be translated into the fourth location C4, where the forming block is collapsed by the retraction of the rod of the cylinder 59 (Fig. 9) which raises the lower lateral wall of the forming block, whose cross section in the vertical direction is thereby decreased to allow the bag to be removed by means which will now be described with reference to Figure 1 1 and to the terminal part of Figure 1. By means of parallel manipulators 98 and a bottom manipulator 99, all fitted with suction cups, mounted on a carriage with suitable horizontal movement means, which can easily be produced by persons skilled in the art and which are therefore not illustrated in detail, the bag lying on the forming block 55, which has reached the location C4 and has been collapsed at this point as stated above, is removed from the forming block, as shown in broken lines and in solid lines in Figure 11 , and is translated to the subsequent operating station D. It is in this step that the edge of the bag with the reinforcing paper pieces 45, 45', if not previously folded at the station B, as described above, is folded on to itself by suitable folders (not shown) while the bag is retained by lateral manipulators 98 and any other necessary manipulators.

The carriage which carries the manipulators 98 and 99 also has vertical folding blades 100 located along the midlines of the lower and upper lateral walls of the bag, these blades being brought towards each other and towards the bag at the correct time, while the lateral manipulators are brought towards each other at the correct time, as shown in Figure 1 1 a, so as to flatten and close the bag, making use of the lateral accordion fold scores 89 with which the bag has been provided. In the same step, the bottom manipulator 99 is brought suitably closer to the lateral manipulators, as shown in broken lines and in solid lines in Figure 1 1 a. In the next step, as shown in Figure 1 1 b, the bottom manipulator 99 rotates through ninety degrees about a vertical axis, so as to align the bottom with the rest of the bag. The bottom manipulator 99 is preferably comb-shaped, to leave portions of the bottom of the bag free. After the steps which have been described, the carriage with the manipulators and folders described above, in the final part of its travel away from the forming block 55, places the free portions of the bottom of the bag on the initial part of a motorized belt conveyor 101 , running round vertical shafts, this conveyor being initially opposite a vertical idle roller 102 carried by horizontal movement means 103 which bring it from the preceding rest position towards the conveyor 101 so as to press on to the conveyor the said free portions of the bottom of the bag which is released at the correct time by the lateral manipulators 98 and by the bottom manipulator 99, and is picked up by the means 101 and 102, the conveyor 101 being activated at the correct time to insert the flattened bag between itself and an adjacent conveyor 104 which is parallel and is also motorized, to flatten and support the bag, these conveyors being synchronized with each other and being driven by a motor with electronic speed and phase control. When the bag has been completely removed from the manipulators 98, 99, 100, these are retracted to the rest position and are prepared for a new cycle, while optoelectronic means (not shown), which have detected the position in space of one of the ends of the bag picked up by the conveyors 101 , 104, cause the conveyors to position the mouth of the bag correctly between cutting means 105 located upstream of the said conveyors, these means making at least a pair of through holes 106 in the reinforced mouth of the bag for the subsequent fitting of the handle, and if necessary making an intermediate hole (not shown) for the fitting of any improvised closure, for example a tie with a bow, if the bag is intended, for example, to contain a gift.

On leaving the conveyors 101 , 104, the bag can be collected and stacked by suitable means and can be sent to the manual cycle for fitting the handles, or, as shown in the variant of Figure 3, the bag can be placed in a subsequent operating station E where it is picked up by the flattened bottom, by gripping means 107 of the mechanical type for example, associated with a vertical carousel 108, there being, for example, four groups of gripping means spaced at equal angular intervals, this carousel also being controlled by means which, on command, rotate it in steps of ninety degrees. The said gripping means 107 are combined with longer gripping means 109, which have suction cups at their ends to hold the lateral walls of the bag at a short distance from the areas provided with the said holes 106 for fitting the handles. After a bag has been picked up by the gripping means 107 and 109 at the location E1 , the carousel 108 rotates through 90° and transfers the bag to the location E2 where it arrives with its mouth opened by the gripping means 109 which have been duly activated for this purpose. Means for fitting the handles M in the holes 106 operate at the location E2. After the carousel 108 has rotated through a further 90°, the bag with its handles reaches the location E3, where means operate to fix the handles M to the bag, for example by knotting their ends inside the bag. It is to be understood that the scope of the invention includes the solution in which means for both fitting and fixing one handle operate at the location E2, while means for fitting and fixing the other handle operate at the next location E3. In the following ninety- degree rotation of the carousel 108, the bag with its handles reaches the location E4, where gripping means 109 are brought together to return the bag to the flattened form, after which these gripping means are pneumatically inactivated and the corresponding mechanical gripping means 107 are opened, so that the bag can be deposited by gravity on the initial part of a conveyor belt 110 where suitable guide means (not shown) are provided to ensure that the bag is positioned transversely there, with the handles M at one side of this conveyor. The conveyor 1 10 is motorized to move the bags away from the carousel 108, and can operate in synchronization with a small upper conveyor 1 1 1 which returns the bags with their handles to the flattened condition in which they left the conveyors 101 , 104 of station D of Figure 1. On leaving the conveyor 1 10, the bags can be collected by stacking and packaging means of any suitable type (not shown).

With reference to Figures 22 to 28, a description will now be given of a variant embodiment which enables large-format bags to be produced by combining two sheets, one after the other, thus making it possible to use normal-format printing machines and to limit the costs of customizing the sheets. Figure 22 shows how two adjacent stacks of sheets 8, 8' are positioned at station A, these sheets being fed simultaneously or in succession, by the means of feeding 23 and tilting 29 described with reference to Figures 1 , 4 and 5, to the conveyor 1 , which transfers them to a station G located upstream of station B in which the reinforcing paper pieces are applied, where the conveyor halts temporarily and is inactivated pneumatically with respect to the front sheet F which is held, by underlying suction cup means 1 13 for example, while the conveyor remains pneumatically active with respect to the following sheet F'. In the next step, as shown in Figures 22, 23 and 24, at least one parallel line of adhesive 1 14 is applied to the rear transverse side of the rear sheet F, by a gun 1 15 which slides on guide and sliding block means 116 driven by power means 1 17 and which is positioned laterally with respect to the sheet at the start and end of its active travel, as shown in Figure 23. In the next step, deflectors 1 18 are raised by suitable means, so that, as shown in Figure 25, when the conveyor 1 advances the downstream sheet F', the sheet F is positioned with its front edge above the line of adhesive 1 14, and in this condition the sheet F' is correctly halted by the electronic means which control the motor for advancing the conveyor 1 , this conveyor remaining pneumatically active with respect to the said sheet F'. Other suitable means similar to the means 1 13 (not shown) can be provided if necessary to help to hold the sheet F'. In the next step, as shown in Figure 26, the deflectors 1 18 are lowered and a presser 119, operated by an actuator 120 mounted for example on the gantry frame 121 which supports the said guide and sliding block means 1 16, is made to move downwards on to the front end of the rear sheet F', and this presser remains in the active position of pressing against the counter-piece 122 until the line of adhesive 1 14 has set and has firmly joined the sheets F and F' together. In the next step, the presser 1 19 is raised as shown in Figure 27, the suction cups 113 and any others are inactivated, and the conveyor 1 again becomes pneumatically active with respect to the whole article formed by the sheets F and F', and is then activated to transfer this article to station B of Figure 22, as already described for the basic machine. Figure 28 shows how the tubular body for forming a large-format bag, when wrapped around the forming block 55, consists of the sheets F and F' joined together below by the line of adhesive 1 14 which has previously joined the sheets F and F', and joined above by the line of adhesive 54, as already described with reference to the basic machine. The areas of joining of the two sheets are placed near the corners of the forming block 55 at 180° to each other, at the sides of the bag which can be contracted with an accordion fold and therefore in positions where they have little external impact. It is to be understood that the variant which has been described is also considered to be protected in the version in which the sheets to be joined together are drawn from adjacent reels.

Claims

1 ) Method for fabricating paper shopping bags having the same characteristics as those currently made by hand, characterized by the sequence of the following operational steps:

- picking up at least one sheet of paper and/or other material (F) from at least one stack (8) or from at least one reel (3) and placing it on a horizontal surface, with the printed surface facing downwards;

- aligning the sheet against a fixed lateral reference (7); - a first translation step by translating the sheet (F) in the direction of the larger dimension and placing lines of adhesive (43, 43') on it a short distance apart and parallel to the side of the sheet which has previously been brought up to the said fixed reference (7);

- applying paper pieces (45, 45') for reinforcing the future upper longer sides of the bag, to which the handle will be fitted, to the sheet bearing the said lines of adhesive

(43, 43'), at the end of the said first translation movement;

- optionally, folding back on itself in a book-like way the side of the sheet on which the said reinforcing paper pieces (45, 45') have been applied and fixed, so that the paper pieces lie inside the folded edge and are therefore invisible; - picking up the side of the sheet with the reinforcing paper pieces (45, 45') by suitable means which translate the sheet horizontally by a drawing movement in a direction which is at an angle of 90° to the preceding direction of translation, in which step the sheet is positioned under one of the forming blocks of a carousel or transfer device with a vertical axis, which carries other identical forming blocks, suitably spaced apart, and which, on command, is made to rotate, always in the same direction, to move the forming blocks to successive operating locations;

- providing the sheet (F), during the said second translation step, with at least one line of adhesive (54) parallel to one of the shorter sides orientated in the direction of this translation; - applying the paper piece (62) for reinforcing the bottom of the future bag to the smaller vertical wall of the forming block, and retaining it there, the sheet (F) being positioned under this forming block at the end of the said second translation step;

- raising the sheet (F), folding it sharply around the forming block located above it, and fixing the sheet to itself to form a tube, the flaps bearing the said line of adhesive (54) being superimposed on each other, for example on the upper horizontal wall of the forming block;

- suitably scoring the corner areas of the tubular article, during the said step of wrapping the sheet around the forming block to form a tube, and forming suitable Y- shaped scores (89) in the lower and upper horizontal walls of the article, to enable the future front walls of the bag to be contracted by accordion folding;

- transferring the forming block, wrapped in the tubular article and carrying inside it the paper piece (62) for reinforcing the bottom of the future bag, to a subsequent location, in which the upper and lower flaps (L1 , l_2) of the projecting portions of the tubular article are folded on to the said bottom paper piece, and in which first and second lines of adhesive (92, 94) are subsequently applied and the lateral and vertical flaps (L3, L4) of the projecting part of the tubular article are folded in the correct order, to close the bottom of the bag;

- transferring the forming block with the bag closed at its bottom to a subsequent location in which the said folded and glued parts of the bottom are pressed to enable the said lines of adhesive to set and to keep the folded and superimposed flaps correctly flattened;

- transferring the forming block with the bag closed at its bottom to a final location in which the cross section of the forming block is suitably decreased to enable the bag to be removed from it; - accordion-folding and flattening the bag removed from the forming block, and rotating the bottom of the bag through ninety degrees, so that it lies on the bag in a coplanar way;

- making pairs of through holes (66) in the reinforced mouth of the bag, for the future fitting of the handles, and making an intermediate hole if necessary for the application of any improvised means of closure; - collecting the bags in stacks and sending them to a manual cycle for fitting the handles.

2) Method according to Claim 1 , characterized in that the bag which already has holes for fitting the handles is fed to one of the gripping means of a second carousel or transfer device with a vertical axis, which holds the bags by their bottoms and externally by the lateral walls, and which positions the bags in succession in corresponding locations in which the handles (M), made from cord for example, are fitted into the appropriate holes in the open mouth of each bag, in which the handles are knotted, for example on the ends inside the bag, and in which the bag with the handle is subsequently re-flattened and is discharged towards a stacking step.

3) Method according to Claim 1 , in which, during the said first step of horizontal translation of the paper sheet, the rear corner area of the side on which the said lines of adhesive (43, 43') are applied can be provided with a chamfer (41 ) by a cutting operation, while holes (39) are made in the front corner area of the same side, the whole operation being intended to enable the subsequent line of adhesive (54) for closing the tubular paper article around the forming block to act at a certain depth, thus acting on any portions of the sheet which may be folded in a book-like way and which contain the paper pieces reinforcing the longer sides of the mouth of the future bag. 4) Method according to Claim 1 , characterized in that the book-like folding of the edges of the bag reinforced by the paper pieces (45, 45') can be carried out after the step of removing the bag from the forming block of the carousel or transfer device for forming the bag.

5) Method according to Claim 1 , characterized in that, for making large-format bags, two sheets are used, taken from corresponding stacks or reels, and these sheets (F, F') are fixed to each other with at least one line of adhesive (1 14) to form a large-format sheet which is subsequently treated by the step of applying the paper pieces (45, 45') for reinforcing the future upper edge of the bag, and by all the other steps for forming and completing the bag. 6) Machine for fabricating paper shopping bags having the same characteristics as those currently made by hand, characterized in that it comprises:

- means for taking a sheet of paper (F) from a stack (8) or from a reel (3) and for positioning the sheet on a horizontal surface, with the printed surface facing downwards; - means for aligning the said sheet (F) against a fixed lateral reference (7);

- means for effecting a first translation by translating the sheet (F) in the direction of the larger dimension and means for placing lines of adhesive (43, 43') on it a short distance apart and parallel to the side of the sheet which has previously been brought up to the said fixed reference (7); - means which apply paper pieces (45, 45') for reinforcing the future upper longer sides of the bag, to which the handle will be fitted, to the sheet bearing the said lines of adhesive (43, 43') at the end of the said translation movement;

- optional means for folding back on itself in a book-like way the side of the sheet to which the said reinforcing paper pieces (45, 45') have been applied and fixed, so that the paper pieces lie inside the folded edge and are therefore invisible;

- gripping means (52, 52') for gripping the side of the sheet with the reinforcing paper pieces and for translating the sheet horizontally by a drawing movement in a direction which is at an angle of 90° to the preceding direction of translation, the sheet being positioned at the end of this second translation under one of the forming blocks (55) of a carousel or transfer device (56) with a vertical axis, which carries other identical forming blocks (55), suitably spaced apart, and which, on command, is made to rotate, always in the same direction, to move the forming blocks to successive operating locations (C1 , C2, C3, C4);

- means (53) which, during the said second translation step, deposit a line of adhesive (54) on the sheet, along and parallel to one of its shorter sides orientated in the direction of the translation;

- means for applying the paper piece (62) for reinforcing the bottom of the future bag to the smaller vertical wall of the forming block (55), and for retaining it there, the sheet (F) being positioned under this forming block at the end of the said second translation step; - means which, in a first operating location (C1 ) of the said carousel, raise the sheet (F) and fold it closely around the forming block (55) located above it, and then fix the sheet to itself so as to form a tube, with the flaps having the said line of adhesive (54) superimposed for example on the upper horizontal wall of the forming block; - means for suitably scoring the corner areas of the tubular article, during the said step of wrapping the sheet around the forming block to form a tube, and for forming suitable Y-shaped scores (89) in the lower and upper horizontal walls of the article, to enable the future end walls of the bag to be collapsed by accordion folding;

- in the second location (C2) into which is transferred the forming block wrapped in the paper tube which is to form the bag, a portion of which projects from the forming block, and within which the paper piece (62) for reinforcing the bottom of the future bag is located, means (90) are provided to fold the upper and lower flaps (L1 , L2) of the said projecting portion of the tubular article on to the said bottom paper piece, and further means (91 ) are provided to apply first and second vertical lines of adhesive (92, 94) and other means (93, 95) are provided for folding the lateral vertical flaps (L3, L4) of the projecting part of the tubular article, so as to close the bottom of the bag;

- in the third location (C3), into which the forming block (55), wrapped in the future bag closed at its bottom, is transferred, a presser (97) is provided to act on the said folded and glued parts of the bottom of the bag, to enable the said lines of adhesive (92, 94) to set and to keep the folded flaps correctly in a flat condition;

- a fixed guide means (96) holds the folded and glued flaps of the bottom of the bag in the correct position with respect to each other during the transfer between the second (C2) and the third (C3) operating location; - when the forming block (55) with the bag closed at its bottom is transferred to the final operating location (C4), means are provided to decrease the cross section of the forming block, to enable the bag to be removed from it;

- means for accordion folding and flattening the bag removed from the forming block (55) and means for rotating the bottom of the bag through ninety degrees, to place it substantially in coplanar alignment with the bag; - means for making at least one pair of through holes (66) in the reinforced mouth of the bag, for the future fitting of the handles, and for making an intermediate hole if necessary for the application of any improvised means of closure;

- means for collecting the bags in stacks and enabling them to be sent to a subsequent manual cycle for fitting the handles.

7) Machine according to Claim 6, characterized in that, it comprises means for feeding the bag, which already has holes for fitting the handles, to one of the gripping means (107, 109) of a second carousel or transfer device with a vertical axis (108), which holds the bags by their bottoms and externally by the lateral walls, and which positions the bags in succession in corresponding locations (E1 , E2, E3, E4), in which the handles (M), made from cord for example, are fitted into the appropriate holes (106) in the open mouth of each bag, in which the handles are knotted, for example on the ends inside the bag, and in which the bag with the handle is subsequently re-flattened and is discharged on to final means (1 10, 1 11 ) for re- flattening and removal, for example towards a stacking and packaging step.

8) Machine according to Claim 6, characterized in that, during the said first step of horizontal translation of the paper sheet, cutting means (40) are provided to form a chamfer (41 ) on the rear corner area of the side on which the said lines of adhesive (43, 43') are applied, while suitable cutting means (38) make holes (39) in the front corner area of the same side, the whole operation being intended to enable the subsequent line of adhesive (54) for closing the tubular paper article around the forming block (55) to act at a certain depth, thus acting on any portions of the sheet which may be folded in a book-like way and which contain the paper pieces reinforcing the longer sides of the mouth of the future bag. 9) Machine according to Claim 6, in which the first means of translating the paper sheet (F), from which a bag is to be made, comprise a horizontal conveyor (1 ) with perforated parallel belts whose upper branches run on fixed manifolds (2) connected to sources of suction, the sheet being fed to this conveyor with the printed surface facing downwards and being orientated with the larger dimension in the direction of the length of the conveyor, which is driven by a motor with electronic speed and phase control, so that it can be controlled precisely by means which can be programmed according to the format of the sheets used.

10) Machine according to Claim 9, in which the sheets (F) can be drawn from a reel (3) positioned at the side of the said conveyor (1 ) and parallel to it, a set of parallel rollers (4) being provided for the zigzag running of the strip unwound from the said reel, so that the strip is buffered and smoothed and brought to a flat form, at least one pair of parallel motorized rollers (5) being provided to draw the said strip and means being provided to guide the strip transversely on to the initial part of the said conveyor (1 ) which is temporarily stationary, while at the correct time suitable means (6) make a transverse cut to separate the sheet (F) located on the said conveyor (1 ) from the said strip, means being finally provided to align the sheet (F) against a fixed reference (7) positioned in a parallel way on the side of the conveyor (1 ) opposite that which faces the said reel (3).

1 1 ) Machine according to Claim 9, in which the paper sheets (F) can be stacked with the printed surface facing upwards on a palletized stack (8) placed at the side of the initial part of the said conveyor (1 ), positioned on an elevator (9) and having one of its walls bearing on at least one vertical fixed reference wall (10), the said elevator being fixed to a support structure (1 1 ) whose sides carry sliding blocks (12) which slide on vertical guides (13) fixed to a support frame (14), microswitches (15, 15') being provided to signal the low position and the position of maximum raising of the elevator respectively, the sides of the structure (1 1 ) being fixed to the ends of corresponding closed chains (16), the ends of whose vertical portions run round sprockets (17, 18) located respectively in the upper and lower part of the said frame (14), the ends of the horizontal portions of these chains running round sprockets (19) keyed on a timing shaft (20) supported rotatably by a base structure (21 ) and driven by a power unit with an electric motor having two directions of rotation and preferably of the type with electronic speed and phase control, which automatically causes the cyclic raising of the elevator (9), so that the top of the stack of sheets (8) is always correctly positioned next to level sensors (22) and next to a bar with suction cups (23), supported by pairs of composite articulated parallelogram structures (24) pivoted at (25) on the base frame (21 ) and made to oscillate, for example, by suitable cams (26) keyed on a drive shaft (27) on which are also keyed the cams for operating a mechanical safety feeler (28) which acts on the top of the stack (8), in a similar way to the devices used in known systems for automatically feeding sheets to a printing machine.

12) Machine according to Claim 1 1 , the sheet, taken from the stack (8) by the bar with the suction cups (23) which grips it at one side, is translated and positioned on the initial part of an adjacent conveyor with parallel perforated belts (29) which run over manifolds (30) in the shape of a letter U rotated through ninety degrees, with a portion having a large radius of curvature placed opposite the stack (8) and divided into sectors which can be driven selectively by suitable means, the belts running outside these manifolds, on shafts (31 ) parallel to the longitudinal axis of the underlying conveyor (1 ), one of these shafts taking its motion from the cam shaft (27) which also drives a vacuum pump (33) connected to the said manifolds (30), the said conveyor belts (29) being made to complete the removal of the sheet (F) from the top of the stack (8) and to carry it, in a tilting path, above the initial part of the said first translation conveyor (1 ) and above an adjacent support surface (1 12) in the form of a comb, so that the printed surface of the sheet, which was previously facing upwards, is now facing downwards, and means being provided to inactivate the lower sector of the manifolds (30) when the sheet (F) reaches a position above the conveyor (1 ) and the surface (1 12), so that the sheet (F) falls from the belts (29) and its front side, with respect to the direction of movement, may interact with the teeth of a comb (34) which hold it correctly on the surface (1 12) and on the initial part of the conveyor (1 ) which is temporarily stationary, the said teeth of the comb (34) being movable in lateral apertures (35) of the said plane (1 12), and being associated with a sliding block moving on guides (36) located parallel to and between the lower sectors of the manifolds (30) and obtaining its motion, by means of suitable levers, from at least one cam keyed on the said drive shaft (27) for example, these teeth of the comb being made to translate the sheet (F), on command, on to the surface (112) and on to the conveyor (1 ), so as to bring the opposite edge of the said sheet to bear on a fixed reference (7) located at the side of the surface (1 12) and at the side of the conveyor (1 ) opposite that facing the stack (8).

13) Machine according to Claim 12, in which, when the sheet has been aligned against the said fixed references (7), means activate the suction manifolds (2) associated with the belts of the conveyor (1 ) to fix the sheet to these, and means cause the activation of this conveyor, initially at a slow speed, and when the front edge of the sheet (F) is detected by suitable means (37), the conveyor is made to advance at a suitable speed for transferring the sheet, with predetermined centring according to the format, to the subsequent station (B). 14) Machine according to Claim 13, characterized in that, during the translation from the first (A) to the second (B) operating station, means are provided to halt the sheet (F) temporarily, firstly at a station (38) which forms in the sheet a correct number of holes (39) parallel to and a short distance from the front edge with respect to the direction of movement of the sheet, and secondly at a station (40) which makes a diagonal chamfering cut (41 ) in the corner area of the rear side of the sheet, opposite the portion of the sheet in which the said holes (39) are formed.

15) Machine according to Claim 13, characterized in that, during the translation from the first (A) to the second (B) operating station, at a short and exact distance from the said longitudinal side of the sheet on which the corner chamfer (41 ) is formed, suitable stationary means (42) dispense lines of adhesive (43, 43') which, when the sheet halts at the second station (B), are suitably aligned with magazines (44, 44') which contain the paper pieces (45, 45') for reinforcing the future upper edge of the bag, and these paper pieces are picked up by means (46) with suction cups from the said magazines and are applied to the portions of the sheet with the said lines of adhesive (43, 43'), so as to be fixed firmly to the sheet.

16) Machine according to Claim 15, characterized in that, in a variant embodiment, the means for dispensing the lines of adhesive (43, 43') and for applying the said reinforcing paper pieces (45, 45') can act on a more inward portion of the sheet, spaced apart from the edge of the sheet by a distance substantially equal to the width of the paper pieces. 17) Machine according to Claim 15, characterized in that, in a variant embodiment, the means for dispensing the lines of adhesive (43, 43') and for applying the said reinforcing paper pieces (45, 45') can be such that they fix to the sheet two parallel adjacent pairs of the said paper pieces, which are subsequently superimposed on each other after the subsequent folding step which forms the future reinforced upper edge of the bag.

18) Machine according to Claim 15, characterized in that, in the step of applying the reinforcing paper pieces (45, 45'), the underlying side portion of the sheet bears on a folder (50) which initially acts to oppose the said means (46) for applying the paper pieces, and which is supported by rotation means which, on command, rotate it through 180°, about its longitudinal edge (50'), means being provided to position on the sheet (F), next to the said edge (50') of the folder (50) and parallel to the latter, the front edge of a blade (51 ) which was initially in a raised position, and which acts as a counter-piece during the step of folding the sheet and on to which is turned over the portion of the sheet which is folded by the folder (50) and is usually provided with the reinforcing paper pieces (45, 45'), while the sheet is temporarily retained by suitable means (150, 250), this blade (51 ) being connected to means which, following the active travel of the folder (50), translate it away from the folder and from the conveyor (1 ), so as to insert the portion of sheet folded and reinforced by the paper pieces between a pair of grippers (52, 52') which at the correct time have been brought up to the folder and which are then made to close to grip the folded portion of the sheet, while at the correct time the said blade (51 ) is retracted to the rest position, the grippers being subsequently activated to translate the sheet to the bag forming station (C). 19) Machine according to Claim 6, in which there are, for example, four forming blocks (55) at the bag forming station, and the blocks project from and are spaced at equal angular intervals on a carousel with a vertical axis (56), which by suitable means is made to rotate, on command, through ninety degrees, the said forming blocks (55) being positioned on edge, with the smaller lateral walls at the top and bottom and in a horizontal position, being fixed with respect to their larger vertical lateral walls, their smaller upper lateral walls and their front vertical walls, while the lower smaller lateral wall of each forming block is fixed on sliding blocks (57) which slide on diagonal guides (58) and are connected to a linear actuator (59) which, on command, can raise or lower the sliding blocks (57) with the lower wall, the said movable lower lateral wall of the forming block being made to complete a lower portion of the other three adjacent walls of the forming block when it is in the low position, so that, when the movable wall is raised, the depth of the block is suitably decreased, this characteristic being used to facilitate the removal of the bag from the forming block at the end of the forming cycle. 20) Machine according to Claim 19, in which the vertical bottom wall of each forming block (55) is provided with suction cups (61 ) for retaining the paper piece (62) for reinforcing the bottom of the future bag, the paper piece being taken from a magazine (63) by a parallelepipedal suction manipulator (64) which, after transferring the paper piece to the forming block (55), remains temporarily in association with the forming block to complete the horizontal extension of the four lateral walls of the block in a coplanar way.

21 ) Machine according to Claim 20, in which the manipulator (64), for interaction with the magazine (63) of the bottom paper pieces or with the forming block (55), is hinged horizontally on an arm (66) which is oscillated on a horizontal pivot (67) by the action of first and second levers (68, 68') which follow the profile of a cam (69) keyed on a secondary drive shaft (49), a sprocket (70) being keyed on the shaft (65) which is fixed to the manipulator (64) and being connected by means of a chain (71 ) to a sprocket (72) rotatable on the pivot (67) and connected to first and second levers (73, 73') which follow the profile of a cam (74) keyed on the said drive shaft (49), the manipulator (64) being made to rotate by the latter means, while oscillating on the said arm (66), about the said shaft (70) so that its face on which the suction and gripping means open is positioned initially parallel to the magazine (63) for picking up an end paper piece (62) and subsequently parallel to the vertical wall of the forming block (55), to position and transfer the paper piece on to the pick-up means (61 ) located on this wall of the forming block. 22) Machine according to Claim 18, characterized in that the sheet translated by the said grippers (52, 52') is positioned electronically with a precise reference with respect to the forming block (55) located above it, while the grippers, which open and move away with a precise excess travel, release the sheet on to folding means by which it is firstly precisely retained by suction means (75), these folding means being provided with a central horizontal part (76) opposite and complementary to the lower lateral wall of the forming block (55) located above it, to which are hinged laterally in a book-like way flaps (78, 78') complementary to the vertical lateral walls of the forming block (55), and on whose outer side there are hinged in a parallel way short folding plates (80, 80') connected to pneumatic actuators (81 , 81 ') which initially have their rods retracted, the said central part (76) of the folding means being made to be in the low position at the start of each cycle, and the flaps (78, 78') being made to be in a horizontal position, coplanar with the central part (76) which is mounted on a sliding block (82) slidable on a vertical guide (83) and which can be raised and lowered, on command, by levers (84) and by a cam keyed on a secondary shaft (49'), further cams being mounted on the said secondary shaft (49') and on another parallel shaft (49), the shafts being synchronized with each other, to operate first and second levers (85, 85') acting on corresponding arms (87, 87') fixed to the said flaps (78, 78') to operate the latter, means being provided to ensure that, after the raising of the central part (76) of the folding system, the sheet is pressed by this part against the lower lateral wall of the forming block (55) located above it, and that at the correct time the flaps (78, 78') are rotated upwards through ninety degrees, to fold corresponding portions of the sheet against the vertical lateral walls of the forming block (55), the said cylinders (81 , 81 ') being made to be operated after the raising of the said flaps (78, 78') to fold the final portions of the sheet through a small distance on to the upper wall of the forming block, in such a way that the larger final portion which bears the line of adhesive (54) is located on top of the other portion, a presser (88) operated by a stationary vertical actuator (88') being made to act subsequently to press the said final portions of the sheet on to the upper wall of the forming block, to fix these portions of the sheet firmly together and to complete the formation of the paper tube around the forming block (55) and around the manipulator (64) which is temporarily associated with the forming block, the said smaller upper portion of the sheet preferably being made to be completely surmounted by the larger portion, so that the joint line between these two portions of the sheet appears close to a corner area of the forming block (55).

23) Machine according to Claim 22, characterized in that, in the step in which the said folding means act, as a result of a suitable configuration of the forming block (55) and of the manipulator (64) and of the said folding means (76, 78, 78', 80, 80'), the paper tube wrapped around the forming block (55) and the manipulator (64) is provided with sufficiently deep scored lines on the horizontal corner edges of the said assembly (55, 64), so that, when the paper article is subsequently removed from the forming block, the article remains in the rectangular parallelepipedal shape, provision being made so that, as a result of a suitable configuration of the intermediate part (76) of the folders and of the upper presser (88), and as a result of a suitable configuration of the lower and upper horizontal walls of the forming block (55) and a suitable configuration of the presser (88), the corresponding lower and upper horizontal walls of the tubular paper article are provided with sufficiently deep scored lines (89), in the form of a letter Y, running along the midlines of the said walls and joining in the corner areas of the bottom of the future bag, to impart the necessary capacity of accordion folding to the lateral walls of the bag.

24) Machine according to Claim 22, characterized in that it comprises means by which, after the horizontal line of adhesive (54) has become sufficiently consolidated, the presser (88) is raised and all the said means of folding the sheet are lowered to the rest position, so that the manipulator (64) is inactivated and withdrawn horizontally from the article, while the bottom paper piece (62) remains attached to the suction means (61 ) of the forming block (55), and means are provided by which, in the next step, the carousel (56) rotates through ninety degrees to transfer the forming block with the tubular paper article to the next location, where grippers (90) operated by rectilinear vertical or oscillating actuators act to fold the upper and lower flaps (L1 , L2) of the portion of tube projecting from the forming block (55) on to the bottom paper piece (62), after which a group of guns (91 ) is moved vertically downwards to dispense at least two lines of adhesive (92) along the midline and a short distance therefrom on the bottom paper piece (62) and on the free portions of the said folded flaps (L1 , L2), the vertical flap (L3) being made to be bent, in the next step, by a folder (93) and fixed to the said lines of adhesive (92), and at least two lines of adhesive (94) being made to be dispensed, after the return upward travel of the said guns (91 ), on to the previously folded flap (L3) and to the side of this flap, so as to act on the bottom paper piece (62) and the said flaps (L1 , L2) which were folded initially, a folder (95) finally being made to fold the final flap (L4) on to the penultimate flap (L3).

25) Machine according to Claim 24, characterized in that, after the folders (90) which acted first have been retracted at the correct time to the rest position, while the folders (93, 95) which acted last remain temporarily in the active position, means are provided to rotate the carousel (56) through 90° to transfer the forming block with the bag closed at its bottom to the next operating location, while a fixed curved guide (96) holds the bottom flaps (L1 -L4) in the closed position, and when the forming block reaches the next location, a presser (97) comes into action to exert a uniformly distributed pressure on the bottom of the bag and of the forming block (55) for the time required to ensure the bonding of the said flaps and of the bottom paper piece by means of the said lines of adhesive (92, 94).

26) Machine according to Claim 25, characterized in that, in the next step, after the said presser (97) has been inactivated, means are provided to rotate the carousel (56) through 90°, to transfer the forming block with the bag closed at its bottom to the final location where the forming block is collapsed at the correct time by the retraction of the rod of its internal cylinder (59) which raises the lower lateral wall of the forming block whose cross section is thus decreased in the vertical direction, to enable the bag to be removed by parallel manipulators (98) and by a bottom manipulator (99), all having suction cups, mounted on a carriage with suitable horizontal movement means, the said means acting in such a way that the bag located on the collapsed forming block (55) is picked up, at least by its vertical lateral walls and by its bottom, is removed from the forming block and is translated to a subsequent operating station where, by means of vertical folding blades (100) which are located on the carriage which carries the said manipulators (98, 99), are located on the midlines of the upper and lower lateral walls of the bag, and are brought towards each other and towards the bag at the correct time, the bag is flattened and closed, because of the lateral accordion-folding scores (89) with which it has been provided, the bottom manipulator (99) being made to move towards the said lateral manipulators and rotated through ninety degrees about a vertical axis at the correct time, to flatten the bottom of the bag as well, and to align it with the rest of the bag. 27) Machine according to Claim 26, characterized in that, if the side of the bag having the reinforcing paper pieces (45, 45') has not been folded previously, this side is folded back on itself in a book-like way by suitable folders, after the bag has been removed from the forming block (55) and has been held by the lateral manipulators (98) and any other necessary manipulators. 28) Machine according to Claim 26, in which the said bottom manipulator (99) is preferably comb-shaped, so as to leave portions of the bottom of the bag free, the whole arrangement being such that, when the carriage with the said manipulators and folders completes the final part of its travel away from the forming block (55), it places the free portions of the bottom of the bag on the initial part of a motorized belt conveyor (101 ), running round vertical shafts, this conveyor being initially opposite a vertical idle roller (102) carried by horizontal movement means (103) which bring it from the preceding rest position towards the conveyor (101 ) so as to press on to the conveyor the said free portions of the bottom of the bag which is released at the correct time by the lateral manipulators (98) and by the bottom manipulator (99), and is picked up by the said means (101 , 102), the conveyor (101 ) being activated at the correct time to insert the flattened bag between itself and an adjacent conveyor (104) which is parallel and is also motorized, to flatten and support the bag, these conveyors being synchronized with each other and being driven by a motor with electronic speed and phase control, while the manipulators (98, 99, 100) are retracted, when the bag has been completely removed from them, to the rest position and are prepared for a new cycle, while means which have detected the position in space of one of the ends of the bag picked up by the said conveyors (101 , 104) cause these conveyors to position the mouth of the bag correctly between cutting means (105) located upstream of the said conveyors, these means making at least a pair of through holes (106) in the reinforced mouth of the bag for the subsequent fitting of the handle, and if necessary making an intermediate hole for the fitting of any improvised closure.

29) Machine according to Claim 7, characterized in that it comprises a final station (E) in which the bag is picked up by its flattened bottom by gripping means (107) associated with a vertical carousel (108), there being, for example, four groups of gripping means spaced at equal angular intervals, this carousel also being controlled by means which, on command, rotate it in steps of ninety degrees, and having, in combination with the said gripping means (107), longer gripping means (109, which carry suction cups at their ends to hold the lateral walls of the bag, at a short distance from the areas provided with the said holes (106) for fitting the handles, the said carousel (108) being made to rotate through 90°, after a bag has been picked up by the gripping means (107, 109) in the first location, and transfer the bag to the next location, where the bag arrives with its mouth opened by the gripping means (109) which have been duly activated for this purpose, means being made to operate in the second location to fit the handles (M) into the holes (106), and the bag being made to arrive, after the carousel (108) has rotated through a further 90°, in the third location, where means operate to fix the handles (M) to the bag, for example by knotting their ends inside the bag, and the bag with the handles finally being made to arrive, with the subsequent rotation of the carousel (108) through ninety degrees, at the fourth location, where the gripping means (109) are brought together to return the bag to the flattened form, after which these gripping means are pneumatically inactivated and the corresponding mechanical gripping means (107) are opened, so that the bag can be deposited by gravity on to the initial part of a conveyor belt (1 10) where suitable guide means (not shown) are provided so that the bag is positioned there transversely, with the handles (M) located on one side of this conveyor which is motorized to move the bags away from the carousel (108), together with a parallel conveyor (11 1 ) which returns the bags with their handles to the flattened condition in which they entered the station (E) in question.

30) Machine according to Claim 6, characterized in that, for making large- format bags, two sheets are used, being taken from corresponding stacks or reels, and these sheets (F, F') are fixed together by suitable means (1 13-120) with at least one line of adhesive (1 14) to form a large-format sheet which is then transferred by the suction conveyor (1 ) to the next station (B) where the means for applying the paper pieces (45, 45') for reinforcing the future upper edge of the bag operate, together with any necessary means for folding the side reinforced by these paper pieces in a book-like way.