EP0686464A1 - Waste removal station in a cutting out press - Google Patents

Abstract

An ejection station in a machine for cutting flat workpieces, comprising gripper bars operating in their upper surface, the station comprising a perforated board which is raised by a first control device in order to bear a flat workpiece held by the grippers, the waste from the workpiece being gripped and then conveyed downwards by upper and lower telescopic needles belonging respectively to an upper ejection tool and a lower ejection tool movable vertically by a second and a third control device, characterised in that only the downstream edge of the perforated board is raised, so as to pivot around its upstream edge. The station characterised in that the downstream edge of the board is raised by angular rotation between 1 and 6 deg., preferably between 2 and 4 deg. The ejection tools are skewed parallel to the raised perforated board, and in that they slide along sloping guides at right angles to the board. <IMAGE>

Description

The present invention relates to a waste ejection station in a machine for cutting plate elements such as sheets of paper or cardboard.

For example, these machines are used to cut one or more blanks from each sheet which, after folding and gluing, can be transformed into boxes. Each blank generally includes the six sides of a box, some edges being completed with gluing or closing tabs. Usefully, the waste, that is to say the unused areas of the sheet either between the tabs or between the blanks, are immediately ejected after cutting so as to accumulate in the output stack only finished blanks connected together by a few attachment points.

Such a machine usually comprises first of all an introduction station in which the sheets are removed one by one from the top of a previously installed stack, each sheet then being sent to a margin table. On this table, each sheet is placed in position against front and side cleats before being gripped at its front edge by a series of clamps mounted along a crossbar, each end of which is attached to a side chain train taking the bar, therefore the sheet, to the cutting station comprising a platen press fitted with knives, then to the waste ejection station. If desired, the cutting station can be preceded by a station printing. These processing stations are followed by a receiving station in which each cut sheet is released by the clamps to fall jogged on top of an output stack.

In the ejection station; the sheet is brought flat on a horizontal board which is perforated around the periphery of the zones to be ejected. A horizontal upper ejection tool, in the form of a frame provided with cross members supporting ejection needles or ejectors and / or pressers, is movable in the vertical direction. Under the perforated board is a second horizontal ejection tool also in the form of a frame supporting vertical telescopic needles arranged in correspondence with the upper ejectors. The end of these telescopic needles arrives in the openings of the board slightly below the upper plane. Thus, when the upper tool is lowered onto a cut sheet placed, the respective ejector / telescopic needle combinations pinch the waste which they take down where they fall into a bin.

For reasons of rigidity, the bars supporting the clamps, whether solid or made from profiled bars, have a minimum thickness of 10 millimeters, and usually between 20 and 30 millimeters. So, if the pliers are "at the top", that is to say that they hold the sheet at the level of the upper face of the bar, it is necessary in addition to order the board and the lower tool in an alternating vertical movement down to let the clamp bar pass and up to support the sheet in its passage plane.

However, a reliable and repetitive vertical translation movement of a board or a horizontal frame can only be ensured by acting simultaneously on its four corners. A current ejection station therefore comprises three sets of individual tools controlled in translation, which requires a particularly heavy mechanism, of great inertia and consuming a very large energy.

In addition, the vertical movement of the tools creates, within this station, significant eddies of air harmful for the correct positioning of a sheet weakened by cutting.

The aim of the present invention is an ejection station within a machine for cutting plate elements comprising clamp bars known as "at the top" and the arrangement of the constituent parts of which allows their kinematics to be improved, in particular by reducing the number of movement control devices.

These goals are achieved by an ejection station of the type mentioned above comprising an openwork board which is lifted by a first control device in order to support a plate element from which waste is pinched and then taken down by ejector tools upper and lower in the form of telescopic needles belonging respectively to an upper ejection tool and a lower ejection tool vertically movable under the effect of a second and a third control device, the perforated board being only lifted at its downstream edge so as to pivot around its upstream edge.

For a better understanding of the presentation, the terms "upstream" and "downstream" should be considered in relation to the direction of movement of a sheet, a "upstream" part then being close to the station entrance, a "downstream" part being close to its exit.

Advantageously, the lifting of the downstream edge of the board takes place over a height equivalent to a little more than the thickness of the clamp bar, that is to say according to an angular rotation of between 1 and 6 degrees around its upstream edge, and preferably limited between 2 and 4 degrees.

Thus, after multiple confirmation tests in the workshop, it has been found that, when a sheet stops and the downstream edge of the board rises, the free upstream edge of the sheet lands quickly and without difficulty on the upstream edge remained practically stationary in correspondence with the perforated board. This descent can be carried out all the better if the movement of the board is reduced to the strict minimum, the air swirls are also. This sheet is then perfectly supported as before, certainly slightly biased, the ejector tools can evacuate the waste without problems. By this solution, it was above all possible to simplify the device for controlling the movement of the board and thus to save about twenty percent on the number of parts constituting the control of the movement of the board.

For better coordination of movements, the ejection tools can themselves be at an angle to the perforated board in the raised position and slide orthogonally along oblique guides.

When the perforated board is inserted in lateral translation on the upstream and downstream support strips, the lifting device can act directly on the only downstream strip, if desired, connected to a substantially horizontal guide arm and pivoting around its upstream end.

• la figure 1 est une vue schématique en coupe longitudinale d'une station d'éjection selon l'invention, et
• la figure 2 est une vue schématique en perspective du dispositif de commande de mouvement de la planche ajourée.

The invention will be better understood from the study of an exemplary embodiment taken without any limitation being implied and illustrated in the appended figures, in which:

• FIG. 1 is a schematic view in longitudinal section of an ejection station according to the invention, and
• Figure 2 is a schematic perspective view of the movement control device of the perforated board.

In FIG. 1 is illustrated an ejection station 1 in which plate elements 5, such as sheets of paper or cardboard, are brought to the upper face of an openwork board 10 by clamps 6 mounted on a bar driven by two trains of side chains not shown. When the sheet 5 rests stationary on this board 10, corresponding pairs of upper fixed needles 22 and lower telescopic needles 32 belonging respectively to upper ejection tools 20 and lower 30 pinch a waste zone from above and below to take it, in a downward translational movement out of the sheet 5 and drop it in an underlying tray not shown. Once the sheet 5 has been cleaned, it is again pulled by the pliers 6 towards the outlet of the station situated to the left of the figure.

As illustrated in this FIG. 1, this ejection station 1 has two side windows 2 allowing access to the tools for changing them during the passage from one production to another according to different formats. Tools 20 and 30 are presented both in the form of a frame made from aluminum profiles taken in the vertical direction.

Within this framework are installed a plurality of longitudinal members and crosspieces making it possible to fix, in correspondence, upper ejectors 22, in the form of fixed needles, and lower ejectors 32 in the form of telescopic needles. The upper tool 20 can also support a plurality of pressers to press the sheet 5 against the board 10. The frames of the tools 20 and 30 have at least in their upstream and downstream sides horizontal grooves making it possible to hang them, in a movement of lateral translation through the window 2, on strips of upper 24 and lower 34 supports of the ejection station 1.

Plate 10 is perforated as a function of the waste zones specific to a given format. This board is inserted into a frame also comprising, upstream and downstream, a horizontal groove enabling it to be engaged upstream in a lardon 11 and downstream in a lardon 18.

As illustrated in FIG. 1, the transport clamps 6 hold the sheet 5 on their upper surface. Therefore, it is necessary to regularly lower the board 10 to let through the clamp bar bringing a new sheet; then to reassemble this board 10 so that it comes to correctly support said sheet during the ejection of the waste.

More particularly according to the invention, only the upstream gib 11 is raised to bring the upper upstream edge of the board 10 to the plane XX of arrival of the sheet 5. In the variant illustrated in FIG. 1, the downstream side of the frame of plate 10 is inserted on the upper edge of the downstream lardon fixed 18, this connection, for example at the dovetail, then constituting a pivot 9 of the upward movement of the board 10 induced by the lifting of the downstream gib 11.

As an alternative and as illustrated in FIG. 2, the fixed downstream lardon 18 is, conventionally, horizontal and the upstream lardon 11 is connected to two lateral arms 17 fixed at their upstream end to pivots 8 so as to effect their lifted according to a rotation around these dissociated pivots. As best seen in Figure 1, the rise of the strip 11 to make up for the thickness of the clamp 6 implies a rotation of the board 10 around the pivots 9 (or 8) by an angle alpha between 1 and 6 degrees, in rather is in the range of 2 to 4 degrees. This low angle of rotation makes it possible in particular to keep the method of fixing the frame of the perforated board 10 to the bacon by the simple engagement of the edge of the latter in a corresponding groove on the side of the frame.

As best seen in FIG. 2, the strip 11 is moreover guided in the direction of movement of the sheets by vertical guides 13 and, in the transverse direction, by a guide 13 '' parallel and offset with respect to the wall of the station 1.

More particularly according to the invention and as best seen in FIG. 1, the ejection tools 20 and 30 are installed at an angle in this station 1, that is to say parallel to the perforated board 10 in the raised position. For this, the holding pads 26 of the lardons 24 of the upper tool 20 slide along tubes or guide ribs 27 which are themselves oblique, making, with respect to the vertical, an angle alpha identical to that of rotation of the Plate 10. Symmetrically, the studs 36 linked to the lardons 34 of the lower ejection tool 30 slide along oblique tubes or guide ribs 37 parallel to the guides 27.

As can be seen in this figure, this oblique positioning of the tools 20 and 30 does not in any way hamper the control device in vertical movement. Indeed, the device for controlling the upper ejection tool 20 first comprises a cam 40 connected to the main drive shaft of the cutting machine, the position of this cam being read by a roller belonging to the first branch of a reading lever 41, the other branch of which is connected, mobile in rotation, to a control bar 42. The other end of the bar 42 is pivotally connected to a triple lever 43, the second branch of which is connected pivoting to a synchronization bar 44 oriented along the side wall of station 1, and the third branch of which is pivotally connected to the first upstream pull tab 47 acting on the stud 26 upstream of the tool 20. L the other end of the synchronization bar 44 is pivotally connected to a simple lever 45, the other branch of which is connected, still in pivoting, to the downstream pull rod 46 acting on the downstream stud 26 of the tool 20.

As can easily be understood from FIG. 1, the lifting of the reading lever 41 by the cam 40 pulls down the control bar 42 which results in a simultaneous lifting of the pull tabs 47 therefore a simultaneous lifting of the studs 26, lardons 24 and upper tools 20, and this against the compression of the springs 28. This lifting of tools is carried out during the transfer of a new sheet 5.

Symmetrically, the device for controlling the setting in motion of the ejection tool lower 30 first comprises a cam 50 whose position is read by a reading lever 51 acting on a control bar 52 connected to a triple lever 53. The second branch of this triple lever is connected to the downstream pusher 56 while the third branch is connected, by a synchronization bar 54, to a second lever 55 acting directly on the upstream pusher 57.

Then, the lifting of the reading lever 51 by the cam 50 pulls the control bar 52 to the right which causes a coordinated lifting of the pushers 56 simultaneously mounting the studs 36, lardons 34 and the tool 30, and this against traction springs 38. This operation occurs during the ejection of the waste once a sheet 5 is placed on the board 10.

All the connections of the constituent members of the movement control devices described above being rotational connections, there is no interference with the fact that the tools 20 and 30 move in a translational movement slightly biased relative to the vertical. Advantageously and as best seen in the upper left part of FIG. 1 and in FIG. 2, the device for controlling the movement of the downstream lardon 11 of the board 10 comprises a rod 15 connected in rotation on one side to the sliding stud 12 lardon 11, and on its other side to the downstream end of a lever 16 pivoting at its upstream end. This lever 16 is lifted by a cam 19 during the rotation of the lever 45 in an anti-clockwise direction to which it is made integral. This rigid connection between the lever 45 and the cam 19 more or less stalled in advance or in delay ensures perfect synchronization between the prior lifting of the lardon 11 therefore the rotation of the board 10, a possible latency time for the landing of the upstream edge of the sheet 5 on the board, and the lowering in position of the tool 20 simultaneously with the setting up of the tool 30. The continuation of the lowering of the tool 20 against the telescopic needles 32 is accused, at the level of the cam 19, by a strictly circular upstream part.

As we have seen from this presentation, the ejection station 1 according to the invention can operate in a reliable and efficient manner even if the upstream part of the perforated board 10 is no longer set in motion , which allows a substantial saving of parts constituting the movement control device.

Many improvements can be made to this ejection station within the scope of the claims.

Claims (4)

Ejection station within a plate cutting machine comprising gripper bars working in their upper plane, this station comprising an openwork board (10) which is lifted by a first control device (12-16 ) in order to support a plate element (5) held by the clamps and out of which waste is pinched and then taken down by telescopic upper (22) and lower (23) needles belonging respectively to an upper ejection tool (20) and a lower ejection tool (30) movable vertically under the effect of a second (40-47) and a third (50-57) control device, characterized in that the board (10 ) openwork is only lifted at its downstream edge so as to pivot around its upstream edge. Station according to claim 1, characterized in that the lifting of the downstream edge of the board (10) takes place at an angular rotation of between 1 and 6 degrees, and preferably between 2 and 4 degrees. Station according to claim 1, characterized in that the ejection tools (20, 30) are oblique with respect to the raised perforated board (10), and in that they slide orthogonally along guides (27, 37 ) obliques. Station according to claim 1 in which the perforated board (10) is inserted in lateral translation in upstream (11) and downstream (18) support strips, characterized in that the lifting control device (12-16) acts on the only downstream lug (11) which, if desired, is connected to a substantially horizontal guide arm (17) and swivels around its upstream end.

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