EP4302947A1 - Cutting machine - Google Patents

Abstract

The present invention relates to a cutting machine for cutting sheet-shaped material (2) in batches, with a press beam that can be lowered onto the material (2), the press beam having a base body (7) and a press bar (9), the cutting machine having a base body ( 7) has a cooperating drive motor for lowering and / or raising the base body (7), the press bar (9) being arranged in the lowering direction (Z) of the base body (7) leading to the base body (7), the press bar (9) being parallel to the lowering direction (Z) from a starting position in which the press bar (9) is spaced from the base body (7) into a pressing position in which the press bar (9) rests on the base body (7), so that when When the base body (7) is lowered by means of the drive motor, the pressure bar (9) first comes into contact with the material (2) and when the base body (7) is further lowered by means of the drive motor, a distance is created between the base body (7) and the pressure bar (9 ) is reduced until the press bar (9) reaches the pressing position, the cutting machine having a control device (18) for controlling the drive motor, the cutting machine (1) having a monitoring device, the monitoring device being set up to detect a change in position of the press bar (9). with respect to the base body (7), the control device (18) being set up in a first operating mode of the cutting machine (1) to stop the drive motor (8) and/or to trigger a limited return movement of the drive motor (8) in the opposite direction when the monitoring device detects a change in position of the pressure bar (9) with respect to the base body (7).

Description

The invention relates to a cutting machine for cutting sheet-shaped material in batches, with a press bar that can be lowered onto the material, for pressing the sheet-shaped material to be cut in order to carry out a cut.

Such a cutting machine usually has a cutting knife facing an operator side of the cutting machine, which can be moved in a so-called swing cut and, when the cutting knife is driven, cuts through the stacked sheet-shaped material. The material lies on a table of the cutting machine. Immediately adjacent to the cutting knife, as seen from the operator's side, the press bar is arranged behind the cutting knife. This can be lowered onto the material to be cut and thus clamps it between itself and the table during the cut in order to prevent a change in the position of the material to be cut when the cutting process is carried out.

A cutting machine of the aforementioned type is, for example, from EP 3 243 616 A1 known.

In practice, with most cutting machines it is possible to indicate the respective cut. For this purpose, the operator of the cutting machine can lower the press bar in the direction of the material to be cut, which means that Due to the proximity of the press beam to the surface of the material to be cut and the parallelism of the lower front edge of the press beam to the cutting knife, the material to be cut can be optimally aligned with respect to the cutting plane of the cutting knife. During the cut indication, it is usually necessary for the operator to manipulate the stack to be cut under the press beam. In order to exclude any danger to the operator, particularly in terms of fingers being crushed between the press beam and the material to be cut, it must be ensured during the cut indication that the pressing force of the press beam is significantly lower than the pressing force of the press beam when carrying out a cut. The dynamic pressing force with a hint of cutting and a working width of up to 160 cm should preferably be a maximum of 300 N. For cutting machines with a working width of over 160 cm, the pressing force when making the cut should preferably be a maximum of 500 N.

Various solutions are known from the prior art, through which the press bar only acts on the material to be cut with a lower pressing force when carrying out a cut. For example, the aforementioned suggests EP 3 243 616 A1 proposes that the press beam can be actuated by means of hydraulically acting means via a lever arrangement, with a counterweight arrangement acting on the lever arrangement, which acts on the lever arrangement against the weight of the press beam. The hydraulically acting means serve exclusively the function of lowering the press beam for the purpose of clamping the sheet-shaped material during the cut, whereas a separate drive is provided which is only used to indicate the cut and is accordingly designed to be weaker, with the force of this separate drive being sufficient due to the counterweight arrangement is to move the press beam to indicate the cut. The aforementioned publication therefore provides two separate drives.

The object of the present invention is to create a cutting machine which, with a simple design, enables a cut to be carried out. This task is solved by a cutting machine which has the features of patent claim 1.

The cutting machine according to the invention is used for cutting sheet-shaped material in batches and has a press bar that can be lowered onto the material. The press bar has a base body and a press bar, the cutting machine having a drive motor which interacts with the base body for lowering and/or raising the base body, the press bar being arranged leading to the base body in the lowering direction of the base body. The press bar is displaceable parallel to the lowering direction of the base body from a starting position in which the press bar is spaced from the base body into a pressing position in which the press bar rests on the base body. Accordingly, when the base body is lowered by means of the drive motor, the press bar first comes into contact with the material and when the base body is further lowered by means of the drive motor, a distance between the base body and the press bar is reduced until the press bar reaches the pressing position. The cutting machine has a control device for controlling the drive motor. Furthermore, the cutting machine has a monitoring device, wherein the monitoring device is set up to detect a change in position of the press bar with respect to the base body. In a first operating mode of the cutting machine, the control device is set up to stop the drive motor and/or to trigger a limited return movement of the drive motor in the opposite direction when the monitoring device detects a change in position of the press bar with respect to the base body.

In the first operating mode it is thus ensured that the lowering movement of the base body is stopped or even a limited reset movement is carried out as soon as the monitoring device detects a change in position of the press bar with respect to the base body. This prevents the press bar and when operating the cutting machine in the first operating mode the base body comes into contact and the force acting on the base body is transferred to the press bar. Accordingly, in the first Operating mode transmits a relatively low force from the press bar. For example, when the pressure bar is arranged in a vertical direction above the material to be cut, the force transmitted from the pressure bar to the material to be cut is essentially determined by the weight of the pressure bar. In this context, it is considered particularly advantageous if the weight of the pressure bar and elements connected to the pressure bar does not exceed a force of 300 N. Therefore, the first operating mode is suitable for carrying out a cutting indication and it is in particular not necessary to provide a separate drive motor for carrying out the cutting indication and/or to make the drive motor or the power transmission of the drive motor to the base body variable in any way in order to achieve a to ensure lower pressing force when carrying out the cutting indication.

It is considered particularly advantageous if, in a second operating mode of the cutting machine, the base body can be lowered into the pressing position by means of the drive motor in order to press the material onto the press bar under the influence of the base body. In the second operating mode, further lowering of the base body in the direction of the pressure bar is therefore not prevented. It is quite conceivable that switching to the second operating mode can take place when the press bar is no longer in the starting position, but is in an intermediate position between the starting position and the pressing position when the drive motor was stopped in the first operating mode or . the return movement has stopped. In this respect, further lowering of the base body from the intermediate position is enabled in the second operating mode.

The monitoring device can be designed differently. For example, the monitoring device can have a distance sensor that is set up to detect the distance between a reference point of the press bar and a reference point of the base body of the press bar. When a reduction in the distance between the base body and the pressed body is detected by the distance sensor, the monitoring device switches on corresponding output signal is output and transmitted to the control device. The monitoring device can, for example, have a distance sensor in the form of an ultrasonic sensor or laser distance sensor. However, the monitoring device does not necessarily have to measure a distance. It is also entirely conceivable that the monitoring device is designed to output a corresponding signal when the distance between the press bar and the base body falls below a specified distance or a specified stroke path between the press bar and the base body is exceeded, whereby the control device when this signal is received by the control device stops the drive motor and/or triggers a limited return movement of the drive motor in the opposite direction. Such a monitoring device can be designed, for example, as a proximity sensor or as a position switch, also referred to as a limit switch, limit switch or limit switch, or as a mechanical switch or as a light barrier. In principle, different types of sensors can be used in the monitoring device, such as magnetic sensors, optical sensors or inductive sensors.

The monitoring device does not have to interact directly with the press bar and/or the base body, but can also interact with an adjusting element which interacts with the press bar and the base body in such a way that a change in the position of the press bar with respect to the base body, in this respect a change in the distance between the base body and the pressure bar leads to a change in the position and/or orientation of the actuating element. For example, it is conceivable that the press beam has a rack and pinion gear with a rack and a gear meshing with the rack, the rack being mounted in a stationary manner in the press bar and the gear being mounted in a stationary manner in the base body. A change in the distance between the pressure bar and the base body accordingly leads to a change in the rotational position of the gear. The monitoring device can be set up to detect a rotational movement and/or a rotational position of the gear. Accordingly, it is not the change in distance as such that is recorded, but rather a change in the distance via a change in the rotational position of the Gear detected. It is also conceivable that the gear in turn interacts with other elements, for example a rack, and the monitoring device is set up to detect a change in the position of the rack interacting with the gear.

As already explained above, a press bar or, in this case, the base body and the press bar may have a fairly large extension along the cutting edge. In order to ensure that even with a fairly extended press bar, a parallel run of the press bar with respect to the base body is guaranteed, and that tilting of the press bar with respect to the base body is avoided, for example if a foreign body, such as a hand, is between the press bar and the The material to be cut is located, it is considered advantageous if the cutting machine has a synchronization device for synchronizing the displacement movement of the press bar with respect to the base body, the synchronization device having a synchronization element, the synchronization element being coupled to a first section and to a second section of the pressure bar that a displacement movement of the press bar in the area of the first section is transmitted to the second section via the synchronization element, so that the press bar in the area of the second section carries out the same displacement movement, the first and second sections being in the longitudinal direction of the press bar, thus parallel to the cutting edge of the cutting knife, are spaced apart. The synchronization element thus synchronizes the displacement movement of the press bar in the area of the two sections. The synchronization device also ensures that reliable stopping of the drive motor is ensured regardless of the positioning of the monitoring device or regardless of which section of the pressure bar the monitoring device monitors.

The synchronization element can be, for example, a synchronization shaft, a synchronization lever or a synchronization rod.

It is considered particularly advantageous if the monitoring device has a sensor for detecting the position of the synchronization element. In this respect, the monitoring device is set up to detect a change in the position or orientation of the synchronization element. The change in the position of the synchronization element can be used to infer a corresponding change in the distance between the base body and the pressure bar, since these are coupled to the synchronization element. Since local changes in distance also lead to a change in the position of the synchronization element, changes in distance can be detected particularly reliably.

The synchronization element is preferably designed as a synchronization shaft, with at least two gears being mounted in the base body to convert the displacement movement of the pressure bar into a rotational movement of the synchronization shaft. In connection with a synchronous shaft, it is considered particularly advantageous if the monitoring device is set up to detect a rotational movement and/or a rotational position of the synchronous shaft.

In connection with a synchronous shaft, it is considered particularly advantageous if the gears are designed as a rack and pinion gear with a rack and a gear meshing with the rack, the racks being mounted in a stationary manner and at a distance from one another in the pressure bar and the gears being mounted in a stationary manner in the base body are, wherein the gears are part of the synchronous shaft and / or interact with the synchronous shaft. The synchronous shaft is preferably mounted in the base body.

It is considered particularly advantageous in connection with a synchronous shaft if the synchronous shaft has a triggering element which projects in the radial direction, the triggering element interacting with the monitoring device, the monitoring device having a detection area, the triggering element depending on the rotational position of the synchronizing shaft is inside or outside the detection area. In this context, it is considered particularly advantageous if the monitoring device is designed as a proximity sensor, distance sensor or as a light barrier.

It is considered particularly advantageous if the pressure bar and the base body have teeth arranged like a comb and grooves formed between the teeth, with a feed saddle of the cutting machine also having teeth arranged like a comb and grooves formed between the teeth, with the teeth of the feed saddle in the foremost position of the feed saddle engage in the grooves of the press bar and the base body. It is considered particularly advantageous if the base body has a comb section facing the pressure bar and a head section facing away from the pressure bar, the comb section having the teeth arranged like a comb, a support section spanning the teeth being formed between the head section and the comb section. The support section serves to mechanically stabilize the teeth during the pressing process, in that the teeth are supported on the support section on the side facing away from the press bar. The comb section and the support section are preferably formed in one piece.

It is considered particularly advantageous if the synchronization element and/or the monitoring device are arranged in the head section of the base body.

In a preferred embodiment, the drive motor for lowering and/or raising the base body is an electric motor, for example a servo motor. The problem, particularly when using an electric motor, is that force control of an electric motor is often very complex. In addition, electric motors often have the disadvantage that electric motors sometimes react relatively slowly, so that an electric motor cannot be stopped immediately, so that even when the electric motor is switched off, a certain amount of overrun of the electric motor occurs. Due to the design according to the invention, these disadvantages do not occur in the present case or only to a lesser extent Carry. In an embodiment in which a limited restoring movement of the drive motor is triggered, the overtravel can be compensated for by the limited restoring movement. Alternatively or additionally, the displacement path from the starting position to the pressing position can be chosen to be larger than the overtravel path in order to prevent the pressing bar and the base body from coming into contact.

A displacement path from the starting position to the pressing position is preferably at least 5 mm, in particular 5 mm to 25 mm. In this respect, the pressure bar is at least 5 mm, preferably 5 mm to 25 mm, apart from the base body in the starting position. These dimensions have proven to be particularly advantageous in order to reliably prevent the base body from acting on the pressure bar when the drive motor overruns.

It is considered particularly advantageous if the drive motor interacts with a screw jack. A screw jack ensures a particularly high power transmission and correspondingly high pressing force of the press beam. Furthermore, a screw jack is particularly advantageous in that a rotary movement of the drive motor can be converted into a linear movement of the base body particularly easily and efficiently via a screw jack.

It is considered particularly advantageous if the drive motor is designed in such a way that force is transmitted from the drive motor to the base body at two opposite ends of the base body. For this purpose, it is considered particularly advantageous if only a single drive motor is used, with transmission being transmitted to both ends via a synchronous shaft coupled to the drive shaft of the drive motor, which extends parallel to the longitudinal extent of the press beam. For example, in a preferred embodiment it is provided that the drive motor drives a first screw jack and a second screw jack, the two screw jacks being connected to the base body at ends facing away in the longitudinal direction Base body are connected in order to move the base body parallel for the purpose of lowering and raising the base body. The two screw jacks are preferably arranged below a cutting table of the cutting machine and spaced apart from one another in the transverse direction of the cutting machine. The screw jacks are coupled to one another via a synchronous shaft coupled to the screw jacks, so that the lifting movements of the two screw jacks are synchronized. Accordingly, this synchronization shaft could also be referred to as a synchronization element for synchronizing the displacement movement of the base body. The drive motor is preferably also arranged below the cutting table and coupled directly to one of the two screw jacks.

In order to achieve a particularly high level of accuracy when moving the press bar in the base body and in particular to avoid the press bar evading in the presence of an obstacle or even tilting of the press bar relative to the base body, it is considered particularly advantageous if the base body has linear guides for guiding the Displacement movement of the press bar. The linear guide is preferably designed as a plain bearing.

It is considered particularly advantageous if several guide rods are connected to the press bar, the respective guide rod extending essentially parallel to the lowering direction of the base body, at least two linear guides being provided in the base body for the respective guide rod, these linear guides in the lowering direction of the base body are spaced apart from each other. In an embodiment in which the pressure bar is connected to racks, it is considered particularly advantageous if the racks form the guide rods.

It is considered particularly advantageous if the press bar is transferred from the pressing position to the starting position with the support of gravity, preferably exclusively with the support of gravity. Accordingly, it is considered particularly advantageous if no additional drive means or The like are necessary to transfer the press bar from the pressing position to the starting position. Since the transfer of the press bar from the pressing position to the starting position is carried out with the aid of gravity, the press bar remains in its position due to its own weight when the base body is lifted by means of the drive motor until the starting position is reached and the base body then takes the press bar with it. Using travel limiters, for example stops, when moving the press bar using gravity, it can be ensured that the press bar does not move beyond the starting position. These stops can be attached, for example, to the guide rods and/or the racks.

The pressure bar and the base body preferably consist of a metal or a metal alloy, for example steel. A further element, for example an element made of elastic material and/or plastic, can certainly be attached to the leading front of the pressure bar.

It is considered particularly advantageous if the base body is mounted vertically displaceably in a machine frame, with the press bar being mounted vertically displaceably in the base body. It is considered particularly advantageous if the pressure bar is mounted exclusively in the base body.

It is considered particularly advantageous if the cutting machine has one or more spring force elements, with the pressing bar being moved from the starting position into the pressing position against a restoring force of the spring force element or elements. The spring force elements can be, for example, a mechanical spring, for example a torsion spring. The spring force elements are preferably not arranged directly between a front side of the base body and a back side of the press bar, so that the spring force elements do not hinder full-surface contact of the front side of the base body on the back side of the press bar in the pressing position. The spring force elements could, for example, be arranged such that the spring force elements act on a synchronization element. It is also It is quite conceivable that the spring force elements are arranged in the area of the guide rods in an embodiment with guide rods attached to the press bar.

In order to avoid deformation or even damage to the press bar during the pressing process, it is considered particularly advantageous if the press bar has a thickness of at least 5 mm, preferably a thickness of 5 mm to 10 mm.

Fig. 1

eine Ausführungsform der Schneidmaschine in einer Frontansicht, somit von der Bedienerseite her gesehen,

Fig. 2

einen Teilbereich der Schneidmaschine gemäß Fig. 1 in einer Innenansicht von der Frontseite aus gesehen,

Fig. 3

einen Pressbalken der Schneidmaschine gemäß Fig. 1 in einer isolierten Darstellung in einer Rückansicht,

Fig. 4

einen Teilbereich der Pressleiste gemäß Fig. 3 in einem Ausgangszustand in einer Ansicht gemäß dem Pfeil IV in Fig. 5,

Fig. 5

die Pressleiste in einer Ansicht gemäß dem Pfeil V in Fig. 4,

Fig. 6

den Pressbalken gemäß Fig. 3 in einem Zwischenzustand in einer Ansicht gemäß dem Pfeil VI in Fig. 7,

Fig. 7

den Pressbalken in einer Ansicht gemäß dem Pfeil VII in Fig. 6,

Fig. 8

den Pressbalken gemäß Fig. 3 in einem Endzustand in einer Ansicht gemäß dem Pfeil VIII in Fig. 9,

Fig. 9

den Pressbalken in einer Ansicht gemäß dem Pfeil IX in Fig. 8,

Fig. 10

einen Teilbereich des Pressbalkens gemäß Fig. 4 in einer perspektivischen Ansicht,

Fig. 11

einen Teilbereich des Pressbalkens gemäß Fig. 6 in einer perspektivischen Ansicht.

In the following figures, the invention is explained in more detail using the embodiment shown in the figures, without being limited to this. Show it:

Fig. 1

an embodiment of the cutting machine in a front view, thus seen from the operator's side,

Fig. 2

a portion of the cutting machine according to Fig. 1 in an interior view seen from the front,

Fig. 3

a press bar according to the cutting machine Fig. 1 in an isolated representation in a rear view,

Fig. 4

a portion of the pressure bar Fig. 3 in an initial state in a view according to arrow IV in Fig. 5 ,

Fig. 5

the press bar in a view according to arrow V in Fig. 4 ,

Fig. 6

according to the press beam Fig. 3 in an intermediate state in a view according to arrow VI in Fig. 7 ,

Fig. 7

the press beam in a view according to arrow VII in Fig. 6 ,

Fig. 8

according to the press beam Fig. 3 in a final state in a view according to arrow VIII in Fig. 9 ,

Fig. 9

the press beam in a view according to arrow IX in Fig. 8 ,

Fig. 10

a portion of the press beam according to Fig. 4 in a perspective view,

Fig. 11

a portion of the press beam according to Fig. 6 in a perspective view.

The cutting machine 1 is used to cut stacked sheet-shaped material 2, for example paper, cardboard, foil and the like. The cutting machine 1 has a working width, here in the Y direction, of approximately 160 cm. A cutting knife 4 and a press beam 5 are movably mounted in a machine frame 3. The cutting knife 4 can be moved via a guide in an oscillating cut, and can therefore be moved vertically (Z direction) with a superimposed horizontal (y direction) movement component. In the Fig. 1 the cutting blade 4 is in the upper position. A receiving table 6 of the cutting machine 1 is used to hold the material to be cut and the cut material 2. When the cutting knife 4 and the press bar 5 are raised, a passage is formed in the machine frame 3 between the press bar 5 and the table for receiving the material 2. In the table 6 a cutting bar is introduced, with the cutting knife 4 of the cutting machine 1 penetrating the cutting bar in the lowered position of the cutting knife 4. The movement of the cutting knife 4 is driven by a drive, not shown. Seen from the operator's side, thus in a front view of the cutting machine 1, the press beam 5 is arranged behind the cutting knife 4, adjacent to it, whereby the press beam 5 can be lowered and raised in the Z direction in a plane parallel to the cutting knife 4 . The press bar 5 serves to press the stacked sheet-shaped material 2 against the cutting table 6 in order to hold the stacked material 2 during the cut with the cutting knife 4. Furthermore, the press bar 5 is used to carry out a cutting indication.

Like this in particular Fig. 3 to 9 As can be seen, the press beam 5 in this case is designed in several parts. The press beam 5 has a base body 7, which interacts with a drive motor 8 for lowering and raising the base body 7. This drive motor 8 is in the present case designed as an electric motor. Furthermore, the press bar 5 has a press bar 9, this press bar 9 being arranged leading to the base body 7 in the lowering direction Z of the base body 7. In this case, the lowering direction Z corresponds to the vertical direction. In the present case, the pressure bar 8 is under the influence of the base body 7 with respect to the base body 7 parallel to the lowering direction Z from a starting position which is in the Fig. 4 is shown in a pressing position, which is in the Fig. 8 is shown, movable. In the pressing position, the base body 7 rests on the press bar 9 on the back of the press bar 9 facing away from the material 2. Accordingly, in the pressing position, the press bar 9 and the base body 7 are in contact and the force applied to the base body 7 by means of the drive motor 8 is transmitted to the press bar 9 and thus to the material 2 to be pressed.

Because the press bar 9 is arranged in the lowering direction Z of the base body 7 in advance of the base body 7 and is mounted in the base body 7 so that it can move parallel to the lowering direction Z with respect to the base body 7, when the base body 7 is lowered by means of the drive motor 8, the press bar 9 comes first with the material 2 in contact without the base body 7 pressing on the pressure bar 9. When the base body 7 is lowered further by means of the drive motor 8, the distance between the base body 7 and the press bar 9 decreases until the pressing position is reached. Only when the base body 7 rests on the back of the press bar 9, insofar as the pressing position has been reached, is the force acting on the base body 7 transferred to the press bar 9 and via the press bar 9 to the material 2, which rests on the table 6 Pressing the material 2. Accordingly, the force of the pressure bar 9 acting on the material 2 before reaching the pressing position is relatively low and essentially determined by the weight of the pressure bar 9.

One and the same drive motor 8 is used both for carrying out a cut indication by means of the press beam 5 and for pressing the material 2 by means of the press beam 5. In order to ensure that the press bar 5 only applies a much lower pressing force when carrying out a cut than is necessary when carrying out a cut, the cutting machine 1 has a monitoring device, the monitoring device being set up to detect a change in the position of the press bar 9 with respect to of the base body 7, namely to detect a reduction in the distance between the press bar 9 and the base body 7 of the press beam 5. In a first operating mode of the cutting machine 1, which serves to indicate the cut, this monitoring device is active, so that when a reduction in the distance between the base body 7 and the pressure bar 9 is detected by the monitoring device, the control device 18 stops the drive motor 8 and / or a limited restoring movement of the Drive motor 8 triggers in the opposite direction. This ensures that when the cutting machine 1 is operated in the first operating mode, thus the operating mode for carrying out the cutting indication, the base body 7 and the press bar 9 do not come into contact with one another, so that no force is transmitted from the base body 7 to the press bar 9. Accordingly, the pressing force with which the press bar 9 acts on the material 2 is much lower in the first operating mode and is essentially determined by the weight of the press bar 9. In the first operating mode, the risk of injury, particularly with regard to crushing fingers or hands, of operating personnel is avoided or at least reduced, thereby ensuring a high level of safety. In addition, due to the low contact pressure of the pressure bar 9, the material 2 to be cut can be aligned.

In a second operating mode of the cutting machine 1, the monitoring device is inactive, so that the base body 7 can be lowered into the pressing position by means of the drive motor 8 in order to press the material under the action of the base body 7 onto the press bar 9 between the table 6 and the press bar 9, as this in the 8 and 9 is shown.

Both the pressure bar 9 and the base body 9 have teeth 23 arranged like a comb and grooves formed between the teeth 23. A feed saddle of the cutting machine 1 has corresponding teeth arranged like a comb and grooves formed between the teeth, the teeth of the feed saddle engaging in the grooves of the pressure bar 9 and the base body 7 in the foremost position of the feed saddle. The base body 7 has a comb section 22 facing the press bar 9 and a head section 15 facing away from the press bar 9, the comb section 22 having the teeth 23 arranged like a comb, with a tooth 23 spanning the teeth 23 in the Y direction between the head section 15 and the comb section 22 Support section 24 is formed. The support section 24 serves to mechanically stabilize the teeth 23 during the pressing process, in that the teeth 23 are supported on the support section 24 on the side facing away from the press bar 9. In the present case, the support section 24 is plate-shaped.

As already stated, the press beam 5 is lowered and raised by means of an electric drive motor 8. This drive motor 8 is arranged below the cutting table 6 and is arranged laterally offset from the cutting table 6 in the machine frame 3. The drive motor 8 interacts with a first screw jack 11 and a second screw jack 11. These two screw jacks 11 are offset from one another in the transverse direction Y of the cutting machine 1 and thus in the longitudinal direction of the press bar 9 and are coupled to one another via a synchronous shaft 12. Due to the coupling via the synchronous shaft 12, the lifting movements of the screw jacks 11 are synchronized with one another. The respective screw jack 11 is connected to a connecting rod 13, the respective connecting rod 13 in turn being connected to the base body 7 on opposite sides of the base body 7. The base body 7 as such is in turn guided in the area of the opposite sides in a vertically aligned linear guide formed in the machine frame 3 to guide the vertical movement of the press beam 5.

The press bar 9 is mounted in the base body 7 via three vertically aligned racks 14 which are fixedly connected to the press bar 9. The racks 14 are mounted in plain bearings 19. At the upper end of the racks 14, a stop element 20 is attached, the press bar 9 being held in the base body 7 via this stop element 20 and it is ensured that the press bar 9 does not move beyond the starting position with respect to the base body 7. The respective stop element 20 rests against a housing 21 in the starting position, with the shaft 16 passing through the housing 21. A gear wheel which is connected in a rotationally fixed manner to the shaft 16 is mounted in the housings 21, with the respective rack 14 meshing with the gear mounted in the housing. Since the three racks 14 are coupled via the gears to the common shaft 16 and to the pressure bar 9 are coupled, a rotational movement of the shaft 16 leads to a lifting movement of the pressure bar 9 and vice versa. The common shaft 16 therefore serves as a synchronization element to synchronize the lifting movements in different sections of the press bar 9, so that a synchronous lowering movement of the press bar 9 is ensured. In the present case, the monitoring device has a sensor designed as a proximity sensor 10, which is also arranged in the head section 15 of the base body 7 adjacent to the shaft 16. The proximity sensor 10 cooperates with a triggering element 17, this triggering element 17 being connected in a rotationally fixed manner to the common shaft 16 and protruding in the circumferential direction of the shaft 16 relative to the shaft 16. The proximity sensor 10 is set up to detect whether the trigger element 17 is in the detection range of the proximity sensor 10. Depending on the rotational position of the shaft 16, the trigger element 17 is located inside or outside the detection range of the proximity sensor 10. This becomes particularly clear when comparing the Fig. 5 , 7 and 9 , which show the press beam 5 in different states and thus the common shaft 16 in different states Fig. 5 shows a state in which the press bar 9 is spaced from the material 2 to be cut. Accordingly, the press bar 9 is in its initial state with respect to the base body 7, in which the press bar 9 is maximally spaced from the base body 7. In this state, the trigger element 17 covers a measuring head of the proximity sensor 10 and is therefore in a detection range of the proximity sensor 10. If the base body 7 is lowered further, the press bar 9 comes into contact with the material 2 to be cut, so that when the base body 7 is lowered further, the press bar 9 is displaced with respect to the base body 7, this displacement movement is transmitted to the shaft 16 via the racks 14 and the gears meshing with the racks 14. As a result, the rotational position of the shaft 16 is changed and the trigger element 17 is pivoted out of the detection range of the proximity sensor 10. A state in which the press bar 9 rests on the material 2 to be cut and is in an intermediate position between the starting position and the pressing position is in the Fig. 7 shown. In this state, the triggering element 17 no longer covers the measuring head, so that the triggering element 17 is outside the detection range of the proximity sensor 10. Accordingly, the proximity sensor 10 detects the change in the distance between the press bar 9 and the base body 7 via the rotational position of the shaft 16 coupled to the trigger element 17 and the drive motor 8 is stopped and the press bar 9 remains in the 6 and 7 shown intermediate position in which the material 2 is pressed against the table 6 essentially with the weight of the pressure bar 9.

Only when switching to the second operating mode of the cutting machine 1 can the base body 7 be lowered further into the pressing position by means of the drive motor 8, in which the base body 7 rests against the press bar 9 on the side of the press bar 9 facing away from the material 2 to be cut. In this state, force is transmitted from the base body 7 to the press bar 9 and the material 2 to be cut is pressed against the cutting table 6 with high pressing force. In this state, a cut can then be made with the cutting knife 4 without the risk of the material 2 to be cut changing its orientation.

Reference symbol list

1

cutting machine

2

Good

3

Machine frame

4

cutting knife

5

press beam

6

cutting table

7

Basic body

8th

drive motor

9

Press bar

10

Proximity sensor

11

screw jack

12

synchronous shaft

13

connecting rod

14

Rack

15

Head section

16

Wave

17

Trigger element

18

Control device

19

bearings

20

stop element

21

Housing

22

ridge section

23

Tooth

24

Support section

Claims (15)

Cutting machine (1) for cutting sheet-shaped material (2) in batches with a press beam (5) which can be lowered onto the material (2), the press beam (5) having a base body (7) and a press bar (9), the cutting machine ( 1) has a drive motor (8) which interacts with the base body (7) for lowering and/or raising the base body (7), the pressure bar (9) leading in the lowering direction (Z) of the base body (7) to the base body (7) is arranged, wherein the press bar (9) is parallel to the lowering direction (Z) from a starting position in which the press bar (9) is spaced from the base body (7) into a pressing position in which the press bar (9) is on the base body (7) is displaceable, so that when the base body (7) is lowered by means of the drive motor (8), the pressure bar (9) first comes into contact with the material (2) and when the base body (7) is lowered further by means of the drive motor ( 8) a distance between the base body (7) and the press bar (9) decreases until the press bar (9) reaches the pressing position, the cutting machine (1) having a control device (18) for controlling the drive motor (8), the Cutting machine (1) has a monitoring device, the monitoring device being set up to detect a change in position of the pressure bar (9) with respect to the base body (7), the control device (18) being set up in a first operating mode of the cutting machine (1) to do so. to stop the drive motor (8) and/or to trigger a limited return movement of the drive motor (8) in the opposite direction when the monitoring device detects a change in position of the pressure bar (9) with respect to the base body (7). Cutting machine according to claim 1, wherein in a second operating mode of the cutting machine (1), the base body (7) can be lowered into the pressing position by means of the drive motor (8) in order to produce the material (2) under the influence of the Press the base body (7) onto the press bar (9). Cutting machine according to one of claims 1 or 2, wherein the cutting machine (1) has a synchronization device for synchronizing the displacement movement of the press bar (9), the synchronization device having a synchronization element, the synchronization element having a first section and a second section of the pressure bar ( 9) is coupled in such a way that a displacement movement of the press bar (9) in the area of the first section is transmitted to the second section via the synchronization element, so that the press bar carries out the same displacement movement in the area of the second section, the first and second sections in the longitudinal direction (Y) of the pressure bar (9) are spaced apart. Cutting machine according to claim 3, wherein the monitoring device detects a position of the synchronization element. Cutting machine according to claim 3 or 4, wherein the synchronization element is designed as a synchronization shaft (16), at least two gears being mounted in the base body (7) for converting the displacement movement of the pressure bar (9) into a rotational movement of the synchronization shaft (16). Cutting machine according to claim 5, wherein the gears are designed as a rack and pinion gear with a rack (14) and a gear meshing with the rack (14), the racks (14) being mounted in a stationary manner in the press bar (9) and the gears in a stationary manner in the Base body (7) are mounted, the gears being part of the synchronizing shaft (16) and/or interacting with the synchronizing shaft (16). Cutting machine according to one of claims 5 to 6, wherein the synchronous shaft (16) has a triggering element (17) projecting in the radial direction, the triggering element (17) being connected to the monitoring device interacts, the monitoring device having a detection area, the trigger element (17) being located inside or outside the detection area depending on the rotational position of the synchronous shaft (16). Cutting machine according to one of claims 3 to 7, wherein the pressure bar (9) and the base body (7) have teeth (23) arranged like a comb and grooves formed between the teeth (23), the base body (7) being one of the pressure bar (9). facing comb section (22) and a head section (15) facing away from the pressure bar (9), the comb section (22) having the teeth (23) arranged like a comb, with the teeth between the head section (15) and the comb section (22). (23) spanning support section (24) is formed, wherein the synchronization element is arranged in the head section of the base body (7). Cutting machine according to one of claims 1 to 8, wherein the drive motor (8) for lowering and/or raising the base body (7) is designed as an electric motor, preferably as a servo motor. Cutting machine according to one of claims 1 to 9, wherein the drive motor (8) cooperates with a screw jack (11). Cutting machine according to one of claims 1 to 10, wherein the pressing bar (7) is transferred from the pressing position to the starting position exclusively with the support of gravity. Cutting machine according to one of claims 1 to 11, wherein a displacement path from the starting position to the pressing position is at least 5 mm, preferably 5 mm to 25 mm. Cutting machine according to one of claims 1 to 12, wherein the press bar (9) and the base body (9) consist of a metal or a metal alloy. Cutting machine according to one of claims 1 to 13, wherein the base body (7) is mounted in a vertically displaceable manner in a machine frame (3) of the cutting machine (1), the pressure bar (9) being mounted in a vertically displaceable manner in the base body (7). Cutting machine according to one of claims 1 to 14, wherein the cutting machine (1) has one or more spring force elements, the pressing bar (9) being displaced from the starting position into the pressing position against a restoring force of the spring force element or elements.

Images