EP1151833B1 - Apparatus for positioning sheets in a machine station - Google Patents

Abstract

A movable shelf which supports a marginal zone of a sheet is moved by actuators. A sheet gripper (15,16) which travels with the shelf during its displacement grips a sheet marginal zone. The sheet gripper is connected to the shelf by an articulation comprising several levers (10,18) forming a parallelogram articulated about horizontal pivoting axes (11,13,17,19). A permanently compressed spring piston (24) eliminates radial play of the pivoting axes and a transverse leaf spring eliminates lateral play.

Description

The present invention relates to a device for positioning leaves in a station of a leaf processing machine, comprising a mobile tablet for supporting at least one marginal area of a sheet, actuators means driving the tablet moving in its plan, and pinch means accompanying the tablet in the said displacement, able to grasp the said marginal area of a sheet between a organ clip-sheets and the tablet, and release it.

In machines for processing paper sheets, cardboard compact, corrugated cardboard, such as stationary presses multiple, the leaves must be positioned very precisely as well in the longitudinal direction than in the transverse direction in each of the stations they cross. Usually, when introducing a sheet into machine, the front edge of the machine is grasped by a transport device, such as that a clamp bar, comprising a plurality of clamps mounted on a crossbar, secured to lateral chains, subsequently taking this sheet in the following machine processing stations, such as cutting station, waste ejection station and others. Terms "forward", "longitudinal", "transverse" and "lateral" are used here by reference in the sense in which the leaves progress in the machine. In these stations, the problem of positioning the sheet is solved through the positioning of the shaping tools with respect to the stopping positions of the clamp bar. Precision and productivity of processing steps The following are therefore conditioned by the accuracy of the gripping.

Stacks of leaves are brought on pallets and introduced into a feeder. The feeder ensures a regular feeding of the leaves towards the margin table, which causes the sheet sheets, allows their gripping and their introduction to the following stations.

In commonly used positioning devices, the sheet is stuck on the margin table against front and side cleats by means of advancing members such as rollers or strips of materials elastic upper, descending in support on the table, or a pair of rollers arranged above and below the table. In the case of leaves raw materials, the front and side cleats used are arranged exactly compared to the references of the following stations. The leaf is quickly thrust against the cleats by the advancing members, then seized by a clamp bar. The cleats are then retracted and the clamp bar can pull the sheet in the next treatment station and position it precisely compared to the tools of the platinum of this station.

The problem of positioning is particularly delicate when the leaf has undergone one or more prior treatment (s), such as printing or creasing fold lines because the following treatments should be done very accurately with reference to the previous treatment. he it is therefore useful to equip the positioning devices with position correction systems.

DE-A-3916405 discloses a positioning device in which the cleats are motorized so that they can command a variation of their position and in which a print mark or other, resulting from prior treatment, can be identified by means of optoelectronic reading in order to adjust the position of the cleats, and therefore the sheet, directly according to the measured position of such mark. However, lug positioning devices imply that each sheet is practically stopped during the entire duration of his jogging and adjustment, which significantly limits the rate of scrolling leaves in the machine.

Patent CH-A-693,378, published 15.07.2003 of the applicant describes a device positioning of sheets in the station of introduction of a machine of sheet processing, of the defined type of input, making it possible to operate this machine at significantly higher rates. The clip-leaf organ present in the form of a transverse bar carrying fingers, the whole forming a comb arranged above the tablet, with studs side integral with the bar and articulated each at a single pivot point located at the mobile tablet. The clip-leaf organ is controlled on the one hand by a spring under pressure arranged between the bar and the tablet, tending to press the fingers of the clip-leaf member against the tablet, and on the other hand by one or two control levers of the introduction station, connected by a telescopic pendulum rod at the rear of the bar, whose pushing the opening of the clip-leaf member by pivoting.

The positioning method according to CH 0671/99 uses a horizontal tablet, which is driven by actuators, for example linear electric motors, on the one hand in a movement back and forth longitudinal and secondly in complementary movements of correction in longitudinal and / or transverse and / or rotational translation around a vertical axis. This process consists, from the tablet in position rear starting, to engage the pinching means of the sheet on the tablet and then order the actuators to advance the tablet and, if necessary, sideways and / or sideways, depending on the readings of the coordinates position of the sheet by optoelectronic means, performed during in advance of the tablet, so as to bring the front edge of the sheet into the clamps of a clip bar in a precise and predetermined position, to release the clamping means of the positioning device, then to bring the tablet back to the starting position.

This process makes it possible to substantially increase the rate of machine, to reach values up to twelve thousand sheets / hour, then that cleat devices made it possible to achieve only the order of eight thousand leaves / hour. However, this positioning device is not free of defects:

The actuation of the opening control lever (s) of the clip-on member generates a shock, therefore a quasi-force instant; the center of inertia of this organ being distinct from its axis of pivoting, the resultant forces has a horizontal component that is exercised on the actuators. In particular, when the control lever of the bar of the clip-leaf member only exists on one side, its thrust on the bar via a connecting rod generates a moment of rotation which interferes with a rotation correction of the position of the sheet.

Even in the case where two control levers act from each side on the clip-leaf member, their pushing can cause a deviation, that is, an error in the stopping position of the tablet that can reach a few tenths of a millimeter. Such a deviation is troublesome, particularly in the case where the sheet to be treated bears an impression, of which some edges must coincide exactly with cuts.

Moreover, at the very high speeds that must allow this device, the cyclical appearance of a horizontal component of a force at the opening of the clip-sheet member may interfere with the setting of side linear motors, making the position correction system inoperative. In extreme cases, there may be a resonance between this parasitic force and these motors, causing a stuffing of the machine.

The object of the present invention is to overcome the above defects.

This goal is achieved in a device of the defined type of input by the the clip-on member is connected to the tablet by at least one articulation comprising a plurality of levers forming a parallelogram Speak clearly.

In the device according to the invention the implementation of the opening control of the clip-leaf organ hardly generates of horizontal parasitic force that may be exerted on the actuators of moving the tablet carrying the clip-on system.

The articulation may include a fixed amount, in solidarity with the tablet, accommodating an upper fixed pivot axis and an axis of lower fixed pivot, arranged substantially one above the other.

Preferably, the clip-sheet member is connected to the pivot by a lever actuator and a return lever forming an articulated parallelogram.

The joint may in particular comprise a top lever actuator, articulated in rotation in its central part around the axis of upper fixed pivot, articulated in rotation at its first end to a control lever of the pinch means and at its second end to a movable upright, a lower return lever articulated in rotation at its first end around the lower fixed pivot axis and hinged in rotation at its second end at the lower end of said movable post, said mobile upright being integral with the clip-sheet member.

Preferably, a spring piston acts permanently on the lever lower return, so as to apply the clip-leaf member on the tablet.

This type of articulation presents by nature a very slight radial play at axis level, which can, at the time of opening the clip-leaf member, cause a parasitic effect on the actuators moving the tablet. To counteract this game, the movable upright of the clip-leaf organ is connected to the fixed upright by a spring piston, articulated in rotation by its first end to said fixed amount and by its second end to the said moving amount. This spring piston is preferably compressed in permanently.

Preferably, the device comprises an articulation at each transverse end of the clip-leaf member, said clip-leaf member comprising a transverse beam and a plurality of fingers oriented towards the front of the device forming a first comb with the beam, arranged above the front edge of the tablet, the so-called front edge of the tablet presenting the profile of a second comb, complementary to the first comb, to pinch the said marginal area of a sheet between them.

The mounting of the beam constituting the clip-leaf member on the lateral amounts, by means of a system of levers forming articulated parallelograms on each side, normally implies a slight play lateral, between moving parts, which can generate parasitic interference with the lateral movement of the actuators of the tablet. To eliminate this lateral clearance, the device according to the invention can comprise at minus a leaf spring, flexible in a vertical plane and rigid in the direction cross-section, connecting the clip-leaf member to a lateral upright integral with the Tablet.

In particular, the device may comprise a pair of leaf springs, polyester reinforced with fiberglass or simply steel spring, each fixed on the one hand to a substantially horizontal plate, secured to a said amount, and secondly to a plate secured to the end of the beam of the clip-leaf organ.

• la figure 1 montre une vue en perspective d'un dispositif selon l'invention.
• la figure 2 montre une vue en élévation latérale de l'articulation entre l'organe pince-feuilles et la tablette de la figure 1, en position ouverte.
• la figure 3 montre une vue en coupe selon le plan ... de la figure 1 de la même articulation en position fermée; ainsi qu'une pince de barre de pince et l'extrémité de la table de marge.

Other features and advantages of the device according to the invention will become apparent to those skilled in the art from the following description of an embodiment of the invention, in connection with the drawing, where:

• Figure 1 shows a perspective view of a device according to the invention.
• Figure 2 shows a side elevational view of the articulation between the clip-sheet member and the tablet of Figure 1, in the open position.
• Figure 3 shows a sectional view along the plane ... of Figure 1 of the same joint in the closed position; as well as a clamp bar clamp and the end of the margin table.

Figure 1 shows, in a 3/4 rear perspective view, the entire positioning device for gripping a press shaping. A mobile tablet 1 is mounted on a frame 2 by via three actuator assemblies 3, 4, 5: the tablet 1 is articulated on three vertical pivots, a central pivot and two lateral pivots, respectively integral with three sliding carriages sliding on slides longitudinal and transverse. The slides are supported by mobile bars comprising permanent magnets forming the rotor of linear electric motors whose stator rests on pedestals respectively in the center and on the lateral edges of the frame 2. Such actuators with permanent magnets, having a good dynamic performance, are available in commerce; they are for example marketed by Etel (Switzerland) under the reference LMA11 / 50.

The positioning device also comprises position detectors not shown in the figures, namely a pair of front edge detection cells of a sheet arranged transversely side by side and at least one side cell bar allowing detect the lateral edge of this same sheet. The results of the readings of these cells are processed by a microprocessor that also knows the race of the tablet 1, determines the possible positioning error of the sheet relative to its theoretical position and calculates correction instructions addressed to the electric motors of the three actuator assemblies. The correction of the basic back-and-forth motion can result in a longitudinal translation in more or less if the sheet is a little too much forward or backward, a transversal translation if the sheet is presented slightly off-center, or rotation, induced by translation differential actuators 3 and 5, if the sheet is slightly crooked.

The device stops in the corrected position in front of a bar of clamps open in the standby position, as shown in Figure 3, where a clamp P is shown, the front edge of the sheet being introduced into the clamps of the clamp bar. The clamps of the clamp bar close and the organ Leaf gripper of the positioning device opens. The tablet returns in rear starting position, linear motors returning to their positions respective neutrals. A new feeding cycle of a sheet can then to start.

As shown in Figure 1, the tablet 1 is attached to each of its lateral ends to a horizontal plate 6 which, on the one hand, accommodates a vertical axis 7 of an actuator group and on the other hand extends vertically upwards by a fixed amount 8, which is secured to the tablet. By convenience of language, the terms "fixed" and "mobile", in the case of the joint, are used here by reference to the tablet 1, although this last is itself mobile in relation to the frame 2. The amount 8 presents a slot 9 in the longitudinal direction of the device, in which is housed an upper actuating lever 10, which pivots around the fixed upright 8 about an upper fixed pivot axis 11, which axis can be made under shape of a smooth bushing passing through the two branches of the fixed upright and the upper lever actuation.

As shown in FIGS. 1 and 2, the lever 10 presents at its first end a pair of holes 12 axis on which articulates a lever of control of the pinching means, this articulation being able to take place via a connecting rod (not shown in the figures).

At its second end, the upper actuating lever 10 is articulated, about an axis of rotation 13, to a mobile upright 14. The axis of rotation 13 can itself be achieved by means of a smooth socket. The amount mobile 14 is secured to the lateral ends of a transverse beam 15. The transverse beam 15 carries fingers 16 oriented towards the front, regularly spaced, forming a comb with the transverse beam 15 and constituting therewith the clip-leaf member.

The amount 14 goes down, as can be seen on Figure 2; at its lower end, it is articulated in rotation about an axis horizontal 17 at the second end of a lower return lever 18, whose first end is articulated in rotation about an axis 19 fixed amount 8. The shafts 17 and 19 can be made by means of smooth bushings.

The fixed amount 8, the upper actuating lever 10, the amount mobile 14 and the lower return lever 18 constitute a parallelogram Speak clearly. In this way, the clip-leaf member secured to the upright 14 describes a translational movement. As a first approximation, this movement of translation can be considered as a vertical translation, because the axes 11 and 19 are located almost vertically one above the other and the movement of the actuating lever 10 is effected on either side of a perpendicular to a perpendicular to and connecting these two axes, on an angle relatively weak.

The return lever 18 carries a superior protrusion 20, itself carrying a side pin 21. A piston 22 spring 23 compressed in Permanently, mounted on the plate 6, acts permanently on the pin 21 of way to fold the lever 18 horizontally and therefore to maintain the clip-on member applied against the tablet 1 in the closed position.

At the moment of opening of the clip-leaf member, a lever of control (not shown) articulated at the axis 12, acts on the piston 22, via the articulated parallelogram, by overcoming the force of the spring 23, for open the clip-on organ.

All axes 11, 13, 17 and 19 are inherently lightweight radial clearance. As a result, the actuation of a control lever on the axis 12 to engender opening of the clip-leaf member can cause a slight shock at the very moment when the actuators operate the final correction of gripping positon. To avoid such a shock, the device comprises a second spring piston 24, articulated in rotation on the one hand to the fixed amount 8 and secondly to the moving amount 14 to be able to follow the deformations of the parallelogram. The spring piston 24 is arranged substantially parallel to the levers 10 and 18, and the spring of this spring piston 24 is permanently compressed. As a result, he exercises a permanent force, substantially perpendicular to the axes 11, 13, 17 and 19 and maintains the maximum spacing between the axes 11 and 13 on the one hand, 17 and 19 on the other hand, so that the radial clearance is removed.

As shown in Figure 1, the device comprises two identical articulations, arranged symmetrically at both ends of the beam 15 of the clip-leaf member. Two control lever systems (unrepresented) perform the same action simultaneously on both joints, so that the process of opening the clip-leaf organ does not generate rotational torque that could interfere with the positional corrections of the actuator assemblies.

The set of two articulations arranged on both sides of the clip-sheet member comprises eight smooth sockets, for two times four axes, allowing the translational movement of the clip-leaf member from bottom to high. This arrangement confers by its nature a certain transversal clearance to the beam 15, between the two joints. To remove this side game, the device comprises on either side of the beam 15, a leaf spring 25 fixed by one of its ends to a fixing plate 26 substantially horizontal, come from a room with the fixed amount 8 or attached jointly to this one. Each leaf spring 25 is fixed by its other end to another horizontal plate 27 integral with the movable beam. In the mode embodiment shown in Figure 1, this second horizontal plate 27 constitutes a protrusion at right angles to the mobile upright 14, itself integral with the beam 15. In the present example, the leaf spring 25 is made of polyester reinforced with fiberglass. It is obvious that this blade-spring 25 could be made from another material with similar elastic characteristics. This blade is flexible in a plane vertical and accompanies the movement of opening and closing of the organ sheet-gripping. However, it is rigid in the transverse direction and blocks a possible transverse sliding of the clip-on member on the sleeves constituting the axes of rotation of the articulated parallelograms.

Claims (10)

1. A device for positioning sheets in a station of a sheet-processing machine, comprising a movable bearing surface (1) for holding at least an edge zone of a said sheet, actuating means (3, 4, 5) moving the bearing surface in the plane thereof, gripping means accompanying the bearing surface in the said movement and adapted to grip or release the said edge zone of a sheet between a sheet-gripping means (15, 16) and the bearing surface, characterised in that the said sheet-gripping means is connected to the bearing surface by at least one joint comprising a number of levers (10, 18) forming an articulated parallelogram around horizontal pivot axes (11, 13, 17, 19).
2. A device according to claim 1, characterised in that the said joint comprises a fixed upright (8) secured to the bearing surface (1) and receiving an upper fixed pivot (11) and a lower fixed pivot (19) disposed substantially one above the other.
3. A device according to claim 2, characterised in that the joint comprises an upper actuating lever (10) connected at its central part for rotation around the upper fixed pivot (11) and rotatably connected at its first end via a shaft (12) to a lever for controlling the gripping means and at its second end (13) to a movable upright (14), and the joint also comprises a lower return lever (18) connected at its first end for rotation around the lower fixed pivot (19) and rotatably connected (17) at its second end to the lower end of the said movable upright, the said movable upright being integral with the sheet-gripping means (15, 16).
4. A device according to claim 3, characterised in that the joint comprises a spring (23) piston (22) permanently acting on the lower return lever (18) so as to press the sheet-gripping means (15, 16) against the bearing surface (1).
5. A device according to claim 4, characterised in that the movable upright (14) integral with the sheet-gripping means (15, 16) is connected to the said fixed upright by a second spring piston (24) rotatably connected via its first end to the said fixed upright (8) and via its second end to the said movable upright (14).
6. A device according to claim 5, characterised in that the said spring piston (24) is permanently compressed.
7. A device according to any of the preceding claims, characterised by a said joint at each transverse end of the sheet-gripping means (15, 16), the said sheet-gripping means comprising a transverse beam (15) and a number of lugs (16) extending towards the front of the device and forming a first comb with the beam, disposed above the front edge of the bearing surface (1), the said front edge of the bearing surface having the profile of a second comb complementary with the first comb in order to grip the said edge zone of a sheet between them.
8. A device according to claim 7, characterised in that it comprises at least one spring strip (25) flexible in a vertical plane and rigid in the transverse direction, connecting the sheet-gripping means (15, 16) to a lateral fixed upright (8).
9. A device according to claim 8, characterised in that it comprises a pair of spring strips (25) of polyester reinforced with glass fibre, each fixed to a substantially horizontal plate (26) integral with a said upright and also fixed to a plate (27) integral with the end of the beam (15) of the sheet-gripping means.
10. A converting press of sheets of paper or cardboard, characterised in that it comprises a positioning device according to any of the preceding claims, disposed between the feed table and the cutting station.

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