EP1153869A2 - Braking device of a machine to work sheet-like elements - Google Patents

Abstract

Sheets (2) with spring grips on the leading edge arrive at a work station and are braked by a flexible element such as a brush (1) which is rotated about an axis (4) by an electromagnetic actuator (5). The movement of the brush is determined by a control loop and regulator which receives brush and actuator positions and takes into account the length and speed of the sheet.

Description

The present invention relates to a braking device at within a receiving station for a sheet material working machine.

Such a machine usually comprises an introduction station in which is installed a stack of sheets which are removed successively from the top of this stack to be sent to a table margin. On this table, each sheet is placed in position against cleats front and side before its front edge is grasped by a series of transport clamps distributed along a crossbar, the ends are integral with lateral drive chains. These pliers transport drives the sheets through the different workstations of the machine. These workstations can in particular be a workstation. cutting followed by a cutting ejection station, to lead to a station in which each sheet is released by the transport clips and jogged on top of a stack formed on a disposal pallet.

To ensure a uniform fall of the sheet with jogging correct, it should be as level as possible when stopped, when opening the transport clamps. For this purpose, the sheet is first supported on arrival at the station by a rear shelf and possibly by two side shelves, which subsequently retract to drop it.

Given the weakening of the leaves which, following cutting and ejecting the cutouts now only form fragile waste grids and given the high speed at which these grids arrive at the receiving station, the only braking by deceleration of the front gripper bar may cause its part to buckle rear which tends to catch up with the front part. This waste grid must therefore be braked by a complementary device acting against its surface.

A device of this type has already been proposed in patent CH 689 977. type comprising at least one flexible braking member, constituted by a long brush extending transversely to the path of said sheets and pivotally mounted around a transverse axis, so that its trajectory around said axis intersects the path of said sheets, the direction of rotation of the end of said flexible braking member intersecting the path of said plate being opposite to the direction of movement thereof. These measures has drive means for pivoting said means of braking as a function of the longitudinal dimension of said sheets and their frequency of passage.

In this device, the movement of the braking member is controlled by a cam connected by a kinematic chain to the mechanism machine drive. This cam acts on this braking member by through a horizontal slide with vertical displacement, the part of which downstream has an upward oblique surface. Since the organ of braking is mounted on a longitudinally movable chassis, its displacement remains constant for sheets with a long dimension longitudinal, then it gradually decreases as we advance the frame with respect to the oblique part of the horizontal slide.

With such a device, the movement of the brake brush is optimal for a given sheet format to the detriment of other formats. It is the passage of the sheet transport clamp bar which determines the possibility of lowering the brake brush. The kinematic link between the lowering control of this brush and the mechanism machine drive limit acceleration communicated to the brake brush.

The object of the present invention is to remedy, at least by part, to the aforementioned drawbacks.

To this end, the present invention relates to a device for braking within a receiving station of an element working machine in sheets, as defined by claim 1.

Thanks to this device, the movement of the braking member is always optimal depending on the format and it can be optimized in real time by function of the sheet scrolling rate.

Optimizing braking of waste grids is a key factor to avoid jamming problems. To allow eliminate the waste grate at high speed without jamming, the grate must be evacuated quickly, the next grid must pass over the current grid brush, the braking brush must pinch the grid to brake it and the grid of the transport clamps must be released as soon as possible to be able to release the pressure from the brake brush so that the rear of the grille falls on the conveyor belt.

Thanks to the device which is the subject of the present invention, it is possible to meet these conditions for each different sheet size and at all machine speeds, since the servo means control the variable speed electric motor with a profile speed adapted to each particular case.

• La figure 1 est une vue latérale d'un schéma de principe de ce dispositif de freinage;
• la figure 2 est un diagramme montrant la relation entre les déplacements de l'organe de freinage et celui de la feuille;
• la figure 3 est un schéma-bloc du logiciel de commande du dispositif de freinage;
• les figures 4-01 à 4-10 sont des schémas explicatifs illustrant les différentes positions de l'organe de freinage correspondant aux états successifs du schéma-bloc de la figure 3;
• la figure 5 représente le schéma-bloc de la boucle d'asservissement utilisée dans les états 6-10 du schéma de la figure 3.

The attached drawing illustrates, very schematically and by way of example, an embodiment of the braking device which is the subject of the present invention.

• Figure 1 is a side view of a block diagram of this braking device;
• FIG. 2 is a diagram showing the relationship between the movements of the braking member and that of the sheet;
• FIG. 3 is a block diagram of the software for controlling the braking device;
• Figures 4-01 to 4-10 are explanatory diagrams illustrating the different positions of the braking member corresponding to the successive states of the block diagram of Figure 3;
• FIG. 5 represents the block diagram of the control loop used in states 6-10 of the diagram of FIG. 3.

For a better understanding of the following description, the upstream and downstream terms are considered with respect to the direction of displacement of leaves: an upstream part facing the station entrance on the right in Figure 1, while a downstream part is oriented to the left of this figure. For the sake of simplicity, only the movement of the braking member flexible, constituted here by a brush 1 extending transversely in the direction of movement F of the sheets 2 is shown since only this device of the present invention and that machines of this type are well known in the field of working on sheets such as cutting or even cutting and printing machines for sheets.

Sheets 2 are therefore moved from right to left in the figure 1 by a crossbar 3 provided with a plurality of clamps which hold the leading edge of the sheets 2 and pull them in the direction of the arrow F. In this example, the brush 1 is pivotally mounted around a transverse axis 4 around from which it is likely to move between two limit positions illustrated by this figure 1 in solid line (high position), respectively in lines mixed (low position). An electromechanical actuator, in this example, a gear motor 5, used to drive this brush 1 in one direction or the other around this transverse pivot axis 4.

Although the example described relates to a braking member constituted by a pivoting brush, it is obvious, for the person skilled in the art, that this member could consist of any suitable braking member, the displacement could be other than circular, for example, parallel or substantially parallel to the path of the sheets 2 to be braked or to the surface of support on which these sheets 2 move.

A detector 6 is used to detect the passage of the clamp bar 3, while another detector 7 is used to detect the raised position of the brush brake 1. Brake brush 1 must be in the raised position to allow the passage of the transverse clamp bar 3 when it must lower to press each sheet 2 against a bearing surface, as soon as the pliers bar 3 has passed and the pliers have released sheet 2.

The block diagram of the control software illustrated in Figure 3 is a simplified representation in which only the states are represented relating to the brush control itself, which explains the absence states 03, 04, 05. As for state 06, it is simplified and actually contains all the initialization procedure which has not been reproduced here insofar as it is not necessary for the understanding of the present invention.

Each state of the block diagram in Figure 3: 01, 02, 06, 07, 08, 09 and 10 is illustrated by a specific diagram of figures 4-01 to 4-10 the number following that of the figure corresponding to the respective state of the block diagram of the figure 3. It should be specified that to allow these commands, an absolute encoder (not shown) is associated with the gear motor 5 for driving the brush brake 1 and that the absolute encoder of the sheet processing machine 2 determines the position of the gripper crossbar 3.

The first two states ST 00 01 and ST 00 02 of this diagram correspond to the machine start-up sequence, which consists of record the position of the brake brush 1 with the motor 5 converter switched on and off. State ST 00 06 corresponds to the movement of the brake brush 1 in its position maximum reading. The difference between the position reached by the brush 1 and the zero position provided by the absolute encoder of the motor 5. If the deviation exceeds a predetermined tolerance, the encoder is reset in this position. The position of the brush is then saved.

In state ST 00 07 the brake brush is slaved in position high called "park" position. The positions of the useful parts of the machine are recorded, as well as that of the clamp bar 3 which allow determine when the brake brush 1 should start to go down.

The descent path of this brake brush 1 is determined according to the position and the speed of advance of the sheets 2 in the machine, in step ST 00 08.

The state ST 00 09 determines the maintenance of the brake brush 1 in the lower position depending on the position of the next gripper bar 3 and its moving speed, or machine speed.

These same parameters will be used in state ST 00 10 to determine the rise path of the brake brush 1 to allow leaving pass the following pliers bar.

The diagram in Figure 2 illustrates the speed profiles of raising and lowering of the brake brush 1 during a cycle of braking of a sheet 2 showing the space between the rise of the brush braking 1 and its descent to allow the passage of the gripper bar 3 as well as the rise and fall tolerances of this brush 1 between the minimum and maximum curves, constituting the window in which the moving the brake brush 1.

The block diagram in Figure 5 represents the loop control used in states 06, 07, 08, 09 and 10 of the block diagram of FIG. 3. This loop comprises a regulator 8 receiving in real time the position of the brake brush 1 and the absolute position of the gear motor 5 drive this brush. This regulator delivers a speed signal compared to the real-time speed of the brake brush. This comparison gives rise to a command speed setpoint of a speed loop 9, which on this basis determines the speed of the gear motor 5 of the brake brush 1 and therefore the instantaneous speed of this brush in depending on the braking parameters chosen.

The operator can adjust the amplitude of movement of the brush. braking 1, i.e. thus determining the braking force. He can also adjust the machine degree to which brush 1 must descend. This choice allows delay the descent of the brush from the moment the detector 6 has detected the passage of the gripper bar 3. It also determines the machine degree to which the brake brush 1 must go up. It finally determines the setting in or brake brush 1 out of service during operation of the machine.

Claims (5)

Braking device within a receiving station of a machine for working elements in sheets, this device comprising at least one braking member (1) extending transversely to the path of said sheets (2) and capable of '' be moved between at least two limit positions, one in which its path meets that of said sheets (2), the other in which said braking member is spaced from the path of said sheets and drive means for moving said braking member between said limit positions as a function of the longitudinal dimension of said sheets (2) and their frequency of passage, characterized in that said means for driving said braking member (1) are constituted by an electromechanical actuator (5) variable speed, connected to servo means (8, 9) recording, in real time, the parameters relating to said longitudinal dimension of the sheets and their f passing frequency. Device according to claim 1, characterized in that said control means comprise a loop having a regulator (8) receiving in real time the position of said braking member (1), as well as the absolute position of the electromechanical actuator (5 ) and making appear at its output a speed signal compared with the real time speed of said braking member, to deliver a speed setpoint to a speed loop (9) for controlling said electromechanical actuator (5). Device according to one of the preceding claims, characterized in that said servo means are programmed to allow the operating parameters of said braking member to be modified. Device according to claim 3, characterized in that one of said parameters which can be modified is the amplitude of movement of said braking member. Device according to claim 3, characterized in that one of said parameters which can be modified is the machine degree at which said braking member must be put into and / or out of action.

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