EP0394707B1 - Device for sequentially feeding sheets to a processing machine - Google Patents

Abstract

The device for sequentially feeding sheets, placed in the feed station of a processing machine, comprises at least one linear feed element (4) passing over an idler pulley (14) and attached at its two ends (16 and 17) onto a drive pulley (18) driven in a rotary to-and-fro movement and at least one low-pressure chamber (2) formed by caissons (3) which can be individually isolated with the aid of a shutter device (73) and connected together to a vacuum source. Discontinuous-circumference rollers (12) are disposed beneath the upper side of the linear feed element (4) and their angular regulation is produced synchronously with the linear movement of the linear feed elements (4). <??>The device finds application in the field of machines for processing corrugated cardboard. <IMAGE>

Description

The present invention relates to a device for sequential introduction of plates into a shaping machine when these plates must be introduced one by one by successive removal of the latter from below a stack placed in a store.

In the feeding station of a shaping machine, such as, for example, a printing and grooving machine or a cutter intended for the shaping of corrugated cardboard plates for the production of packaging, generally comprising tools printing, cutting and local crushing of the cardboard to form subsequent fold lines, the plates contained in a magazine are introduced successively, in phase with the rotation of the printing or cutting tools.

The precision of insertion of each plate into the machine at the appropriate time of the cycle conditions the correct position of the operations carried out on the plates, that is to say the dimensional precision of the finished packing case as well as the precision of the position of the impressions that we made on it. This precision is even more important when the cut and printed blank of the packaging case must then pass through automatic folding stations, which is generally the case today.

One of the introduction devices used in conventional machines, described in European patent No. 0081623-B1, consists in using, to synchronously drive sheets of corrugated cardboard, endless belts which intermittently rotate in one direction and brought against the bottom sheet of a stack by means of a lifting member acting against the upper end of the endless belt, the advance of the endless belts and the lifting member being actuated so that the sheet is driven in synchronism with a subsequent sheet processing machine. To keep the sheets against the belts, continuous vacuum is used, which makes it possible to avoid slippage which is usually associated with the use of belts rotating continuously with the application of intermittent suction pressure. This device is, on the other hand, associated with a mechanism making it possible to interrupt, once in two, the entrainment of the leaves.

Another device for introducing sheets is described in US Pat. No. 4,614,335 which relates to a feeder in which a series of rollers driven in rotation, always in the same direction, is used, with acceleration and deceleration of rotation shingles. These rollers are mounted in the upper closure plate of a vacuum chamber, movable vertically under the effect of a cam and lever assembly. Thus, the departure of the sheets is ensured by moving the lower sheet of the stack, by the upward movement of the vacuum chamber. The same device can, in a particular embodiment described in US Pat. No. 4,681,311 which is an American continuation of the previously cited patent, include rollers or margin belts which introduce, without sliding, the sheets between introduction rollers.

A third device, constituting a variant of the methods and devices mentioned above, is described in detail in the European patent application published under No. 0183361. In this publication, the introductory members are constituted by rollers coated with a material with a high coefficient of friction which cooperate with a member for lifting the stack of sheets. The rollers and the lifting member of the stack of sheets are placed in the enclosure constituted by a vacuum chamber. The rollers are controlled so as to be driven in two directions of rotation, so as to release the stack of sheets from the front stop, intended to allow only one sheet to pass at a time between its lower edge and a surface defined by the plan of the introduction table, constituted by one of the upper walls of the vacuum chamber.

The three devices that we have just described above all have a major drawback with regard to the replacement of the introducer members in contact with the sheets to be introduced. Indeed, these organs are subject to very significant wear and need to be replaced frequently, replacement involves a considerable downtime of the machine, due to the fact that they are arranged in such a way that complete disassembly of the introduction station is often necessary for their replacement. On the other hand, in all devices using rollers as introducers, it is necessary to change some of them more frequently, due to the irregular wear they may exhibit, this due to their position. compared to the variation in format of the sheets to be introduced. Another drawback, and not the least, lies in the fact that, the suction chamber being unique and acting on all the plane defined by the bottom sheet of the stack, it occurs, when working with different sheet formats, vacuum losses which could adversely affect the proper functioning of the device.

A drawback specific to the first of the devices mentioned above resides in the fact that the endless belt lifting member, constituted by an articulated shoe, performs an alternating vertical movement from bottom to top and from top to bottom. The endless belts moving linearly in the direction of the front stop to ensure the introduction of a sheet, there will necessarily be friction between their upper strands and the bearing faces of the lifting members, during the introduction of a sheet. This friction causes, in the long run, the wear of the inner face of the belt which will, in this in this case, it is subjected to wear both on its external face, in contact with the sheets, and on its internal face intended to ensure the adhesion of the endless belt around the control and return pulleys. This arrangement will obviously have a significant impact on the life of the endless belts and will therefore require frequent replacement of the introductory members which, with current constructions, will immobilize the machine for a period corresponding to the time necessary for dismantling the station. of introduction. The replacement time of the introducers being important, it will of course follow a significant drop in the overall performance of the machine.

The present invention aims to provide a simple and rational solution to overcome the aforementioned drawbacks and to provide the user with a means particularly suitable for the work of introducing corrugated cardboard plates into a shaping machine.

To this end, it relates to a device for sequential introduction of plates into a shaping machine, from a stack of plates arranged in a magazine located above a feeding table, provided in its front part with a stop for retaining the plates and two feed rollers, comprising a vacuum chamber, sequential transport means placed side by side and vertically movable, said sequential transport means being constituted by at least one linear member passing around a pulley of return located in the vicinity of the retaining stop and the feed rollers and around a control pulley and means for linearly and vertically driving said sequential transport means, characterized in that the vacuum chamber is formed by boxes placed on either side of the sequential transport means, said boxes being connected to a common vacuum source from which they can be isolated separately by sealing means, in that said linear member is attached at its two ends by means fixing to the control pulley animated by an alternating rotary movement in one direction and in the other, the upper strand of the linear member, extending between the axis of the return pulley and the axis of the control pulley, being supported by a series of rollers having a discontinuous circumference, said rollers being mounted on transverse axes supported at their ends in two side cheeks vertically movable and the linear member being tensioned between the deflection pulley and the control pulley, in that the means for linearly driving said sequential transport means consist of a control shaft animated by a rotary movement pendulum produced by a rod-crank assembly, said control shaft being kinematically connected to the shaft of the control pulley, in that the means for vertically driving said sequential transport means consist of a gear train transmitting the movement continuous rotation of the rod-crank assembly to the axes of each of the discontinuous circumference rollers supporting the upper strand of the linear member, said means for vertically driving the sequential transport means being integral with one of the side cheeks vertically movable and in that the means for linearly driving the sequential transport means are arranged to control the advance of the linear member after it has been lifted by the rollers having a discontinuous circumference.

According to a preferred embodiment of the invention, the linear member consists of a rubberized belt, the free ends of which are fixed to a control pulley driven by an alternating rotation movement.

According to another characteristic of the invention, the means for linearly driving the sequential transport means and the means for vertically driving said sequential transport means are angularly synchronized with respect to each other so that a portion protruding rollers with discontinuous circumference comes into contact with the upper strand of the linear member before the start of the "active" stroke of the latter and that said protruding part of the rollers with discontinuous circumference leaves contact with said upper strand before the start of the "not active" race of it.

One of the advantages obtained thanks to this invention resides essentially in the fact that the replacement of the introduction members can be carried out without tedious disassembly of the introduction station, which reduces, to a significant extent, the time during which the machine is unable to produce. Another advantage obtained using a device according to the invention consists in that, by the shape and the continuous rotary movement of the belt lifting members, the latter is no longer subject to wear untimely of its internal contact face, at the time of the insertion operation.

• La figure 1 est une vue schématique de profil et en coupe partielle d'une station d'introduction,
• La figure 2 représente schématiquement un mode d'entraînement d'un dispositif d'introduction séquentielle,
• La figure 3 est une vue selon A de la figure 2,
• La figure 4 est une vue partielle en plan de la figure 1,
• La figure 5 est une vue en coupe selon V ÷ V de la figure 1,
• La figure 6 est une vue schématique de la chaîne cinématique d'un dispositif d'introduction séquentielle,
• La figure 7 est une vue en coupe selon VII ÷ VII de la figure 6,
• La figure 8 représente schématiquement un caisson de chambre à dépression.
• La figure 9 est une vue schématique de profil des joues latérales supportant les arbres des galets à circonférence discontinue,
• La figure 10 est une vue des moyens de fixation d'un organe linéaire sur sa poulie de commande,
• La figure 11 est une vue en coupe selon XI ÷ XI de la figure 10 et
• La figure 12 est une vue en coupe selon XII ÷ XII de la figure 10.

Other advantages and characteristics of the invention will be highlighted in the description of an embodiment of the device, given by way of nonlimiting example and with reference to the appended drawings, in which:

• FIG. 1 is a schematic profile view and in partial section of an introduction station,
• FIG. 2 schematically represents a drive mode of a sequential introduction device,
• FIG. 3 is a view along A of FIG. 2,
• FIG. 4 is a partial plan view of FIG. 1,
• FIG. 5 is a sectional view along V ÷ V of FIG. 1,
• FIG. 6 is a schematic view of the kinematic chain of a sequential introduction device,
• FIG. 7 is a sectional view along VII ÷ VII of FIG. 6,
• FIG. 8 schematically represents a vacuum chamber box.
• FIG. 9 is a schematic profile view of the lateral cheeks supporting the shafts of the rollers with discontinuous circumference,
• FIG. 10 is a view of the means for fixing a linear member to its control pulley,
• Figure 11 is a sectional view along XI ÷ XI of Figure 10 and
• Figure 12 is a sectional view along XII ÷ XII of Figure 10.

With reference to FIG. 1, the device for sequential introduction of plates, generally designated by the reference 1, comprises a vacuum chamber 2 formed by several boxes 3 placed on either side of the linear introduction members 4 (see figures 4 and 5). The vacuum chamber 2 is supported by transverse beams 5 and 6. The sole 7 located at the front of the vacuum chamber 2 is fixed, by screws not shown, on the transverse beam 5 while the fixing lug 8 located at the rear of the vacuum chamber 2 is, in turn, screwed against a support 9 itself fixed with the screws 10 on the upper face of the transverse beam 6. The vacuum chamber 2 comprises, in the area of the linear insertion members 4, a wall 11 intended, on the one hand, to mechanically link each of the boxes 3 together and, on the other hand, to provide a free space for the rollers with interrupted circumference 12. These circumference rollers interrupted 12 could advantageously be cams. The linear introduction members 4 comprise a linear member 13 which can be a rubberized belt or a linear strap which passes around a idler roller 14, mounted so as to be able to rotate freely on a transverse shaft 15 and attached to its two ends 16 and 17 on a control pulley 18 fixed, for example using a key, on a drive shaft 19. The diameter of the control pulley 18 is chosen so that at least one sector of the 'linear member 13 is always in contact with the control pulley 18, during "active" and "non-active" rotations thereof. The upper strand of the linear introduction member 13 passes over the series of interrupted circumference rollers 12 which are arranged so as to be able to rotate continuously in the direction indicated by the arrow 25. The shape of the interrupted circumference rollers 12 is defined by two portions of a circle 20 and 21. The radius of the portion of a circle 20 is less than the radius of the portion of a circle 21. The connection between the two portions of a circle 20 and 21 is effected by tangents to the circle 20 forming an angle of 60 ° between them. The radius of the portion of a circle 20 is chosen so that, when the roller 12 occupies the position shown in FIG. 1, there is no contact between its linear part and the inner face of the linear member of introduction 13. The radius of the circle portion 21 is chosen, for its part, so that it can lift the upper strand of the linear introduction member 13 during the rotation of the roller 12 in the direction indicated by arrow 25. This lifting of the linear introduction member 13 will bring it into contact with the bottom sheet of a stack (not shown). The control pulley 18 is driven so that the start of its "active" rotation takes place after the circle portion 21 of the roller 12 has come into contact with the internal face of the upper strand of the linear member of introduction 13, that is to say after it has been applied against the lower part of the sheet to be introduced. Thus, by the combined effect of the linear movement in "active" stroke of the member 13, of the lifting thereof by the rollers 12, and of the suction provided by the vacuum chamber 2, the introduction of a sheet under the retaining stop 22 can be made, this in the direction of the introducer rollers 23 and 24 driven at a linear speed substantially equal to or somewhat greater than the linear speed of the introduction member 13. It is obvious that when the "active" stroke of the introduction member has ceased, the kinematics chosen to drive the rollers 12 will cause them to present, facing the internal face of the upper strand of the introduction member, the portion of circle 20 having a diameter such that the upper strand will be placed somewhat below the plane defined by the upper part of the vacuum chamber, thus authorizing the "active" remaining stroke as well as the "non-active" return stroke of the intro organ duction without there being friction between it and the leaves to be introduced.

In the example chosen in FIG. 1, the movement transmitted to the shaft 19 comes from a control shaft 26 animated by a reciprocating rotary movement indicated by the double arrow 27. The transmission of this movement is carried out by means of a toothed wheel 28 mounted on the control shaft 26 and connected by means of a toothed chain or belt 29 to a toothed pinion 30 mounted on the shaft 19. In this figure, these members transmission lines have been shown in dashed lines and the relationships existing between the toothed wheel 28, the toothed pinion 30, the diameter of the control pulley, the rotation drive of the rollers 12 and the angular displacement of the control shaft 26, are chosen so that the linear displacement of the introduction member 13 corresponds substantially to the advance necessary to introduce a sheet whose front edge is in contact with the retaining stop 22, between the introduction rollers 23 and 24.

FIG. 2 schematically represents a second version of the transmission of the movement from the control shaft 26 to the shaft 19. This version replaces the wheel assembly, toothed pinions and toothed chain, 28, 30 and 29 respectively by a train of gear 31 comprising a toothed wheel 32 mounted on the control shaft 26 and connected to the toothed pinion 33 fixed on the shaft 19 by means of an intermediate toothed wheel 34 mounted, so as to be able to rotate freely, on an axis 35 As can be seen in FIG. 2, the linear introduction member 13 is shown in the position it occupies at the end of the "active" travel, that is to say when the fasteners 36 and 37 of the ends 16 and 17 of the introduction member 13 are in their upper position. As can be seen from this figure, we do see that the rear sector of the drive pulley 18 has always remained in contact with the internal face of the introduction member during its "active" rotation and will still remain in contact with this during the "not active" return rotation. The fasteners 36 and 37 are advantageously constituted by a jumper 38 overlapping the control pulley 18 and pinching the ends 16 and 17 of the insertion member 13 under the effect of the tightening of the screws 39. The lateral arrangement of the elements shown on FIG. 2 is shown by FIG. 3 which is a view along A of FIG. 2.

Figure 4 is a partial plan view of Figure 1. In this figure, there is shown schematically the right part of the introduction station which comprises between two side frames 40, of which only the right one has been shown here , the device for sequentially introducing plates 1. For the sake of clarity of the drawing, we have deliberately omitted to show in this figure the retaining stop 22 and the introducer rollers 23 and 24.

As can be seen, the sequential introduction device 1 comprises a flat surface made up of plates 41 and 44 covering both the area located above the boxes 3 that the area located in front and behind the linear introduction members 13. The plates 41, covering the area located in front and behind the introduction members 13, are simple smooth plates, as is the plate 44 placed in the vicinity of the lateral frame 40. The plates 43 which cover the area located above the boxes 3 are, in turn, pierced with a multitude of orifices 45 intended to allow the action of the vacuum on the lower sheet to be introduced in machine. The partial section along line 46 of FIG. 4 shows the way in which the rollers 12 are mounted on their respective shafts 47, so that the vacuum is confined in the boxes 3. To do this, and to isolate the caissons of the zone in which the insertion member 13 is located, provision has been made to mount, on each side of the rollers 12, sealing sleeves 48. The same solution has been used to ensure the sealing between the caissons 3 and the return and control pulleys 18. The arrangement of the drive members of the various shafts shown in this figure will be described later, with reference to Figures 6 and 7.

Figure 5 is a sectional view along V ÷ V of Figure 1 in which there is shown the left part of the sequential introduction device 1 with its other side frame 40. As is apparent from this figure, the boxes 3 of the vacuum chamber 2 are interconnected at their lower part by conduits 50 opening into a collector 51 connected to a vacuum source which may be, for example, a turbine vacuum pump (not shown). FIG. 5 also shows the relative position of the plates 43 and 44 with respect to the insertion members 13. As emerges from this figure, the introduction members 13 supported by the rollers 12 are situated substantially below the defined plane by the upper faces of the plates 43 and 44, when the protruding part of the rollers 12 is not in contact with the upper strand of the introduction members 13. During the rotation of the shaft 47, the protruding part of the rollers 12 will raise the introduction members 13 above the level of the plates 43 and 44 which, when set in motion, will cause the introduction of the bottom sheet of the stack of sheets to be worked.

FIG. 6 represents the kinematic chain of the control members of the sequential introduction device 1. The main movement comes from a drive shaft (not shown) of the shaping machine and it is communicated to a rod-crank assembly 52 constituted by a toothed wheel 53 supported by a shaft 54. A crank pin 55, arranged against one of the faces of the toothed wheel 53, engages in one of the ends of a lever 58. The other end of the lever 58 comprises , in turn, a pin 62 on which is articulated the head of another lever 63 fixed, using a key and a clamping device 64, on the control shaft 26 driving the toothed wheel 32 which will transmit its movement to the control pulley 18, via the toothed pinion 33 and the intermediate wheel 34. It is obvious that the rod-crank assembly 52 can advantageously be replaced, for example, by a control device with cams and levers.

The shaft 54 also supports a toothed wheel 65 meshing with a pinion 66 connected to another toothed wheel 67 which can drive, by means of a pinion 68 mounted so as to be able to be moved laterally on a shaft 69 and, by the fork 70, the double pinion 71 serving as an intermediary for controlling the rotation of each of the pinions 72 driving the shaft 47 of the rollers 12. The assembly which we have just described constitutes in fact a gearbox having the ratios 1: 1 and 1: 2. As shown in FIG. 6, the pinion 68 meshes with the toothed wheel 53, which generates a rapid speed of rotation of the shafts 47 thus forcing the rollers 12 to rotate at the speed of one revolution per machine cycle. The toothed pinions 66 and 68 must, of course, have the same number of teeth. The ratio of 1 to 2 of the rotation control of the shafts 47 of the rollers 12 therefore indifferently allows one or two lifting of the introduction members 13 during a single "active" stroke thereof, which allows, in the in the case of processing large sheets, to introduce a sheet for two feeds of the feeders 13. Sometimes it is desired to interrupt the introduction of the sheets into the machine, for example, for adjustment convenience or adjustment. To this end, provision is made to interrupt the action of the rollers 12 on the linear member 13. One could imagine, for this, momentarily lower the train of rollers 12, as well as their axes 47 and their control means, in a lower position in which there would be no more contact between said rollers 12 and the upper strand of the member 13. FIG. 9 represents such a provision.

Figure 7 is a section along VII ÷ VII of Figure 6 schematically showing the lateral arrangement of the bodies of the kinematic chain. Due to the passage of the cutting line through the various pinions and wheels 53, 65, 66, 67, 68, 71 and 72, the meshing between the toothed wheel 53 and the pinion 68 does not appear in this figure because it occurs in a plane different from that of the section plane.

FIG. 8 schematically represents the sectional view of a box 3 provided in its lower part with a closure device 73 comprising a fixed grid 74 and a movable drawer 75. The fixed grid 74 is provided with lights 76 and the drawer mobile 75 of orifices 77. In a preferred embodiment, the mobile drawer 75 is connected to a pneumatic cylinder 78 which, when actuated, will open or close the openings 76 of the fixed grid 74, thus making it possible to use only the boxes located in the surface represented by the format of the sheets to be inserted.

Figure 9 is a schematic profile view of the side cheeks 90 supporting the axes 47 of the rollers 12 with discontinuous circumference. As we indicated previously, it is advantageous to provide for the deactivation of the sequential introduction device 1. To do this, it is wise to interrupt the action of the rollers 12 on the linear member 13 by moving vertically. This operation is made possible using two eccentric pins 120 and 121 housed in each of the side cheeks 90. The end of the eccentric pin 121 is equipped with a lever 122 held in place by screws 123. The end the eccentric pin 120 is, for its part, fitted with another lever 124 fixed by the screws 125. One end of the lever 122 is connected to the end of the lever 124 by means of a pull tab 126. The other end of the lever 122 is connected to the rod 127 of a pneumatic piston 128. The position shown in FIG. 9 shows the sequential introduction device 1 in operation, that is to say when the lateral cheeks 90 occupy a "high" position. The out of service position has been shown in phantom in this figure.

In the present embodiment, it is necessary to provide a pneumatic piston 128, levers 122 and 124, pull tab 126 and eccentric journals 120 and 121 on each of the side cheeks 90. One could imagine a simplification, using, instead of eccentric journals 120 and 121, through eccentric shafts, which would make it possible to use only a piston and lever assembly.

• Dans un premier temps, on démonte les brides 106 et 109 et l'on retire les extrémités de l'organe linéaire 13 de l'ergot cylindrique 103.
• On appond ensuite le nouvel organe linéaire à celui que l'on désire remplacer, à l'aide d'une ficelle ou d'un morceau de fil de fer que l'on passe dans l'oeillet de l'une des extrémités du nouvel organe linéaire et de l'une des extrémités de l'organe linéaire à remplacer.
• Dans un troisième temps, l'on tire sur l'extrémité libre de l'organe linéaire à remplacer jusqu'à ce que la jonction entre celui-ci et le nouvel organe linéaire apparaisse et que ses oeillets puissent être engagés sur l'ergot cylindrique 103.
• Après cela, on détache l'un de l'autre les deux organes linéaires, on engage les oeillets 104 et 105 du nouvel organe linéaire sur l'ergot cylindrique 103 et l'on serre la bride de serrage 106.
• Pour terminer, on tend l'organe linéaire à l'aide du levier 111 et l'on bloque, en position tendue, l'organe linéaire à l'aide de la bride de serrage 109.

FIG. 10 is a view of the means for fixing a linear member 13 to its control pulley 18. In the embodiment shown, the control pulley 18 has a recess 100 comprising a first face 101 and a second face 102. The face 101 is provided with a cylindrical lug 103 (see FIG. 12). This cylindrical lug 103 is crimped in the face 101. It could, of course, be screwed there. The linear member 13 has at each of its ends an eyelet 104 respectively 105. These eyelets 104 and 105 engage on the lug 103 so that the two ends of the linear member 13 are superimposed at this location. A first clamp 106, having a housing 107 and a thickness substantially less than the thickness represented by the two superimposed ends of the linear member 13, maintains these against the face 101 by means of the screws 108. A second flange clamp 109 (see FIG. 11) holds the linear member against the face 102 of the recess 100. This clamp 109 has a housing 110, and its thickness is substantially less than the thickness of the linear member 13. The linear member 13 is thus made integral with its control pulley 18. It is then necessary to give it a certain tension so that it can work correctly. To this end, provision is made to use a lever 111 (shown in broken lines in FIG. 10). This lever 111 comprises two cylindrical tenons 112 and 113. The cylindrical tenon 112 engages in a bore 114 machined through the control pulley 18 while the tenon 113 is brought into contact with the linear member 13. Thus, the linear member 13 having been secured on the control pulley 18 using the flange 106, it will be easy, by actuating the lever 111 clockwise, to give tension to the linear member 13 and, while maintaining this tension, to then tighten the second clamp 109 on the face 102 of the recess 100 by means screws 115. This type of fixing of the linear member 13 makes it easy to replace it, if necessary, by acting as follows:

• Firstly, the flanges 106 and 109 are dismantled and the ends of the linear member 13 are removed from the cylindrical lug 103.
• Then attach the new linear member to the one you want to replace, using a string or a piece of wire that is passed through the eyelet of one end of the new linear member and one of the ends of the linear member to be replaced.
• Thirdly, pull on the free end of the linear member to be replaced until the junction between it and the new linear member appears and its eyelets can be engaged on the cylindrical lug 103.
• After that, the two linear members are detached from each other, the eyelets 104 and 105 of the new linear member are engaged on the cylindrical lug 103 and the clamping clamp 106 is tightened.
• Finally, the linear member is stretched using the lever 111 and the linear member is blocked in the stretched position using the clamp 109.

This way of proceeding therefore avoids dismantling the introduction station and allows rapid exchange of the linear members 13.

Claims (13)

1. Device for sequential introduction of sheets into a shaping or forming machine from a pile of sheets located in a magazine that is found above a feeding table which is provided with a front gate (22) for holding back the sheets and with two introduction rollers (23, 24), the said device comprising a vacuum chamber (2), sequential transportation means being placed side-by-side and being vertically displaceable, the sequential transportation means being formed of at least a linear member (13) that passes around a return pulley (14) located in the neighbourhood of the front gate (22) and of the two introduction rollers (23, 24) and around a control pulley (18), and means to linearly and vertically drive said sequential transportation means, characterized by the fact that the vacuum chamber (2) is formed by three vacuum boxes (3) placed on each sides of the sequential transportation means, the said boxes (3) being connected to a common source of vacuum and provided with obturation means (73) to enable isolating each box from the said source, by the fact that the said linear member (13) is attached at both of its ends (16, 17) by means of a fixing appliance on the said control pulley (18) which is imparted with a rotating motion alternatively in the one or the other direction, the upper run of the linear member (13) extending between the axis of the return pulley (14) and the axis of the control pulley (18) being supported by a series of small rollers (12) having a non-circular periphery, the said small rollers (12) being mounted on transverse shafts (47) supported at their ends in two lateral plates (90) vertically displaceable, the linear member (13) being placed under tension between the said return pulley (14) and the control pulley (18), by the fact that the said means to drive the said sequential transportation means linearly comprise a second shaft (26) being imparted with a pendular rotating motion produced by a connecting rod, crankshaft assembly (52), the said second shaft (26) being kinematically connected to the shaft (19) of the control pulley (18), by the fact that the said means to drive the said sequential transportation means vertically include a train of gears for transmitting the continuous rotation of the third shaft (52) to the transverse shafts (47) of each of the small rollers (12) having a non-circular periphery and supporting the upper run of the linear member (13), the said means to drive the said sequential transportation means vertically being linked with one of the lateral plates (90) vertically displaceable, and by the fact that the means to drive the said sequential transportation means linearly are arranged so that the forward displacement of the linear member (13) occurs when the said linear member has been lifted by the small rollers (12) having a non-circular periphery.
2. Device according to claim 1, characterized by the fact that the linear member (13) comprises a linear strap covered with a coating that insures its adhesion to a sheet to be introduced, the said linear strap being arranged so that each one of its ends has an eye, the shape of which is approximately circular.
3. Device according to claim 2, characterized by the fact that the linear member (13) is constituted by a rubberized strap, the ends of which are not bound together, the said rubberized strap having ends provided with approximately circular eyes.
4. Device according to claim 1, characterized by the fact that the kinematic connection between the shaft of the control pulley (18) and the second shaft (26) is formed by a notched belt (29).
5. Device according to claim 4, characterized by the fact that the kinematic connection between the shaft of the control pulley (18) and the second shaft (26) is formed by a gear train including a toothed wheel (32) and a toothed pinion (33) gearing with an intermediate wheel (34).
6. Device according to claim 1, characterized by the fact that the means to drive the sequential transportation means vertically constitute a gear train that transmits the continuous rotation of the third shaft (52) to the transverse shafts (47) of each of the small rollers (12) having a non-circular periphery, the said gear train having a transmission with a ratio of 1:1 and a ratio of 1:2.
7. Device according to claim 1, characterized by the fact that each of the small rollers (12) having a non-circular periphery is a cam being continually rotated in a single direction.
8. Device according to claim 1, characterized by the fact that the means to drive the sequential transportation means linearly and the means to drive the sequential transportation means vertically are angularly synchronized relative to each other so that the high spot (21) of each of the small rollers (12) having a non-circular periphery comes in contact with the upper run of the linear member (13) prior to the beginning of its movement in a forward direction, and the said high spot (21) of the small rollers (12) having a non-circular periphery moves out of contact with the upper run prior to the beginning of its movement in the opposite direction.
9. Device according to claim 1, characterized by the fact that the obturation means (73) for the boxes (3) constitue a slide-type valve (75).
10. Device according to claim 1, characterized by the fact that the appliance for fixing the linear member (13) on the control pulley (18) includes a cylindrical projection (103) extending from one of the faces (101) of a hollowed-out area (100) made on the said control pulley (18), and on which approximately circular eyelets located at each end of the linear member (13) engage, as well as a first flange (106) centered on the said cylindrical projection (103) and screwed on the face (101) of the control pulley (18), a second flange (109) clamping by means of screws (115) the linear member (13) against the other face (102) of the hollowed-out area (100) made on the said control pulley (18) when the linear member has been placed under the desired amount of tension.
11. Device according to claim 1, characterized by the fact that the linear member (13) is placed under the desired amount of tension by means of a lever (111) having a first pin (112) that engages in the control pulley (18) when the machine is at standstill, and a second pin (113) acting on the linear member (13).
12. Device according to claim 1, characterized by the fact that the vertical displacement of the lateral plates (90) is achieved by the rotation of two eccentric spindles (120, 121) effectuated by levers (122, 124) connected to a pull handle (126).
13. Device according to claim 12, characterized by the fact that one of the said levers (122) is actuated by a pneumatic piston (128).

Images