EP0495354A1 - Device for treating fabric-like workpieces, in particular of leather or the like - Google Patents

Abstract

A device (10) for treating fabric-like workpieces (60), in particular of leather or leather substitute, has a cutting device (12) which possesses a knife (18) and by means of which a scarfing operation is carried out on the workpiece (60). It possesses, furthermore, at least one guide element (14) and at least one transport element (16) which is movable counter to a force and to which the force imparts the tendency to move in the direction of the guide element (14), the workpieces (60) being fed to the knife (18) between the guide element (14) and transport element (16), at the same time being in contact with these. So that changes on the workpieces to be treated can be detected during a treatment operation, especially changes in hardness and thickness, it is proposed to provide a sensor device which detects the respective relative position between the guide element (14) and transport element (16). <IMAGE>

Description

The invention relates to a device for processing flap-like workpieces, in particular made of leather, leather substitute or other materials, with a cutting device having a knife, by means of which sharpening or splitting operations are carried out on the workpieces, with at least one guide element and with at least one against a force-movable transport element, which through the force the tendency is awarded to move in the direction of the guide element, the workpieces between the guide element and the transport element being in contact with the latter being fed to the knife.

Such a device is known from DE-A-37 32 059.

The device known from it is a sharpening machine. Sharpening machines are used in the leather processing industry, in particular the shoe industry and the bagging industry, to provide cuts of leather, rubber, plastic or the like by cutting them with a predetermined cross-sectional shape. Cross-sectional shapes have developed certain standard shapes, which are referred to in technical terms as "cuts". Such cuts generally have either a bevel in the area of the edge of the workpiece or a recess with sides parallel to the side surfaces of the workpiece. To define a particular cut of a type of cut, two values are usually sufficient, e.g. the remaining thickness at the trimmed edge of the workpiece and the width of the cut at the surface plane of the workpiece or - in the case of an obliquely cut workpiece - the slope angle of the bevel.

In the known device mentioned at the outset, the guide element is designed as a stationary shoe, which is opposed by a motor-driven feed roller as a transport element. The workpiece to be machined is created by a gap between the guide element and the feed roller transported through this and fed to the knife immediately behind in the direction of transport. The edge to be machined extends in the transport direction and, for example when making an oblique cut, is fed to the cutting edge of the knife at a correspondingly inclined angle. In sharpening machines, the knife is generally designed as a bell knife, in the interior of which the feed roller is partially arranged. The tab-like workpiece slides on the outside of the tab surface on the guide element. The feed roller rests on the opposite other outside of the lobe-like workpiece. The distance between the guide element and the surface line of the feed roller closest to it is determined by the material thickness and the material hardness. The distance between the sliding surface of the guide element and the cutting edge of the knife is determined, for example, in a sharpening process in which a bevel is produced in the region of the edge to be machined, by the remaining thickness at the trimmed edge, ie the thickness corresponds to the distance between Cutting edge and stationary guide element.

If, for example, the remaining thickness at the trimmed edge is to be half the thickness of the workpiece, the thickness of the workpiece to be machined must first be measured before the machining process is carried out, and then the distance between the cutting edge and the guide element must be set to half the value of this thickness .

To determine the thickness, the thickness is determined at some point on the workpiece by means of a thickness measuring device and this value is used as a basis for the setting.

Does the thickness of the workpiece change or do the material properties change, i.e. softer and harder zones alternate, so it cannot be reacted to during a machining process, since there is a fixed setting between the knife and the guide element. Because of this rigid relative position between the knife and guide element, which cannot be changed during a machining process, the machining process would have to be interrupted several times and the distance between the guide element and the transport element adjusted in each case. This process is extremely complex and cumbersome.

It has been found that considerable fluctuations in thickness predominate within natural leather within a flap-like workpiece to be machined, and that the hardness of the material also fluctuates greatly, which is very often the case with other materials or leather substitute materials.

The aforementioned exemplary specification of the machining process, namely that the remaining thickness of the machined edge corresponds to half the thickness of the material when producing a bevel, can then not be met if, for example, the material has an area which is along the edge to be machined is getting thicker. If the thickness value was determined at the end of the edge at which the machining process was started and the guide element for the cutting edge of the knife was adjusted accordingly, the resulting thickness in the area of the thickening leather on the trimmed edge is less than half the thickness . The width of the cut then becomes inappropriately large. If, for example, the hardness of the material changes in such a way that it becomes ever softer along the edge to be machined, the material is compressed more by the contact pressure of the feed roller, ie the "thickness" of the material that is transported through the gap between the feed roller and guide element will decrease. As a result, the cutting edge is no longer halfway between the surface line and the guide element, but relatively closer to the surface line of the feed roller, since this has moved into the material, ie towards the cutting edge. That is, the distance between the surface line and the cutting edge is then less than the distance between the cutting edge and the guide element, so that a thickness of the trimmed edge of the object remains which is more than half the thickness.

These deviations can lead to considerable difficulties in later machining processes.

Comparable problems also occur with so-called splitting machines. When splitting flap-like workpieces, for example, they are fed to a horizontally running band knife, which splits the flap-like workpieces into two partial flaps along the flap plane. The flap-like workpiece, which extends flatly in a horizontal plane, is fed along a front edge of a horizontally running cutting edge of a band knife. The feed takes place in such a way that an approximately cylindrical feed roller, the surface lines of which extend parallel to the horizontal cutting edge, transports the workpiece. On the side of the flap-like workpiece, which is opposite to that on which the feed roller engages, is a guide element, usually in shape a guide plate, provided, the distance between the plate plane and the closest surface line of the feed roller is then determined again by the thickness or hardness of the material.

For example, if the flap-like workpiece is to be split in such a way that two flap-like workpieces of the same thickness are created, the cutting edge of the knife is brought into position so that it comes to rest halfway up the distance between the guide element and the closest surface line of the feed roller. In the known devices, as is also the case with the aforementioned sharpening machines, the guide element is rigid, i.e. to keep at a constant distance from the cutting edge. Here, as previously described in connection with the sharpening process, the same problems occur if the material properties change. If the thickness of the material increases from the end at which the splitting cut is made, viewed in the opposite direction to the transport direction, a splitting result is produced which does not correspond to the exemplary specifications mentioned above, i.e. it does not produce two parts of the same thickness, but the part between the feed roller and the cutting edge is thicker.

If, for example, the material of the workpieces that are being processed becomes ever softer, the feed roller can move further into the material, as mentioned above, compressing it, so that the distance between the cutting edge and the closest surface line of the feed roller is reduced. whereas the distance between the cutting edge and the guide element remains unchanged. This also results in two split workpieces of different thickness.

A disadvantage of the aforementioned sharpening or splitting devices is that changes within the workpieces to be machined, in particular changes in hardness and thickness, cannot be detected, so that they cannot be reacted to.

The object of the present invention is therefore to remedy the situation and to further develop a device of the type mentioned in the introduction such that changes to the workpiece to be machined can be detected during the machining process.

According to the invention the object is achieved in that a sensor device is provided which detects the relative position between the guide element and the movable transport element.

The object is achieved completely because the respective relative position between the guide element and the movable transport element, and in particular changes in this relative position during the processing of a blank, are recorded, which then enables direct statements about the workpiece to be machined. The deflection of the movable guide element is a meaningful measurement, since it stems from direct contact with the material to be worked. The deflection of the transport element is, for example, proportional to the thickness of the workpiece to be machined, so that it can be determined by a simple distance detection whether the thickness of a workpiece to be machined becomes larger or smaller within a machining operation. You can also determine whether the material is softer or harder. In the case of natural materials such as leather, the difference in hardness is greater than that Fluctuations in thickness recede. In the case of leather replacement materials that are manufactured by machine, a fluctuation in thickness may be less than a fluctuation in hardness. In the simplest case, the sensor device is coupled to an optical display which indicates to the operator that, for example, a change is taking place, so that the corresponding machining process can then be terminated. It is of course possible to specify certain tolerance limits within which the thickness of the material to be processed can fluctuate without measures having to be taken. A signal is only generated when such a tolerance limit is exceeded.

The sensor device itself can include a mechanical, optical, electrical or other designed detection of the change in position.

Because the sensor device detects the respective relative position between the guide element and the transport element, the initial thickness of the material to be processed can also be determined at the beginning of a machining process by merely inserting it between the guide element and the transport element. From this, certain machining parameters can then be determined and the cutting device set accordingly. It is then no longer necessary to first carry out a thickness measurement outside the device. In addition to the advantage that an initial detection of material properties of the workpiece to be machined, which can also be carried out during machining, is also possible, it is also possible to detect foreign objects which are inadvertently drawn in. For example, due to carelessness If a piece of clothing or a body part, for example a finger of a processing person, is inserted between the guide element and the transport element, this results in a very strong abrupt deflection of the movable transport element. A threshold value that is exceeded very quickly can then be used to take security measures immediately.

In a further embodiment of the invention, the sensor device is connected to a process unit which converts the measurement signal received from the sensor device into a control signal.

This measure has the advantage that, via the process unit, the measurement signal detected by the sensor device is converted into a corresponding control signal, which then triggers a control process. This measure also has the advantage that an automated machining process is possible which uses the measured values detected by the sensor device directly to control further work processes. This has the advantage that this can be done without the attention of the operator of the device, so that a machining process can possibly be carried out fully automatically. For example, if no workpiece is received between the guide element and the transport element, the transport element taking its maximum position on the guide element due to the force, in particular a spring force, it is possible to use the corresponding measurement signal from the sensor device to drive the cutting device and / or switch off the transport element or switch to a minimum load level. This can then save energy for the drives. Will a workpiece between the guide element and transport element introduced, the change in the signal detected by the sensor device from a zero position can be used to start a certain program sequence, for example to trigger a certain cutting program of several successive cuts or splitting processes.

In a further embodiment of the invention, the process unit is connected to an actuator of a guide element arranged directly in front of the knife, viewed in the direction of transport of the workpieces, and delivers this guide element during machining of a workpiece depending on the measurement signal of the sensor device.

This measure has the advantage that the sharpening or splitting result is automatically adapted to the changed properties. If one takes the case mentioned above as an example that a splitting result is to be achieved in which the splitting products each have half the thickness of the workpiece to be split, and if the workpiece to be split becomes thicker and thicker in the course of a machining process, the transport element is first removed from the Cutting edge deflected and detected by the sensor device. The actuator for the guide element is activated via the process unit such that the distance between the cutting edge and the guide element is then moved away from the cutting edge by half the change in distance between the cutting edge and the transport element. As a result, the transport element then moves again by this half distance in the direction of the cutting edge, so that the distances between the cutting edge and The guide element on the one hand and the cutting edge and the transport element on the other hand are of the same size, so that the desired splitting result, namely two splitting parts of the same thickness, is then achieved again. If other splitting results are required, adjustments are made to achieve the specified splitting result. Appropriate precautionary measures are then taken in the process unit, of course, so that the advancing movement of the transport element due to the positioning of the guide element, which is also detected by the sensor device, is not interpreted as a change signal of the properties of the workpiece, which can be achieved in that for the point in time of placing the guide element, no signals are processed. However, it is also possible to monitor the change in the position of the transport element detected by the sensor device when moving up due to the adjustment of the guide element, since this has to be done by a certain calculable amount. If this dimension is then exceeded or undershot, this is an indication that a further change in the thickness or hardness of the workpiece has already occurred, which is then also detected and evaluated again, so that a reaction can be made.

If changes in the hardness of the material compared to changes in the thickness are to be suppressed, the transport element can be applied to the workpieces under a very high contact pressure. As a result, the material is compressed so strongly that changes in thickness due to fluctuating hardness no longer appear as a measurable size. This can be provided, for example, in the case of leather substitute materials made of plastic materials.

In a further embodiment of the invention, the sensor device detects the position or change in position of the transport element without contact.

This measure has the advantage that no mechanical connection between the sensor device and the transport element is necessary. The transport device must be serviced at regular intervals because it is exposed to high mechanical loads. To do this, it must be removed from the editing facility. Because there is no mechanical connection to the sensor device, this is very easily possible.

In a further embodiment of the invention, as is known per se, the transport element is designed as a driven feed roller.

This measure has the advantage that a component is used as the transport element which has design features that can be easily used for determining the position and determining the change in position by means of the sensor device. For example, it is possible to detect the laterally projecting axle journals of the axle shaft about which the feed roller rotates as a feature for detecting the relative position relative to the guide element. In particular, as mentioned above, this is also possible in a simple, non-contact manner, so that, for example, the laterally projecting axle journals interact with optical or electrical sensor means which detect the respective position of these parts.

In a further embodiment of the invention, the feed roller is carried by a feed bearing arm which can be pivoted about an axis, and the sensor device detects the change in the angle of rotation of the feed bearing arm.

This measure has the advantage that the change in position of the feed roller can be detected at a distance from the processing point. For example, the rotational movement of the feed bearing arm about its articulation axis can be detected, which, depending on how long the arm is formed, is more or less far from the work station, so that the sensor device is not exposed to the dirt that is in the vicinity of the Knife arise during the machining process. This also opens up the possibility of retrofitting already existing devices which are provided with such a feed bearing arm with a sensor device without the need for expensive retrofitting work.

In a further embodiment of the invention, mechanical means are provided which result in correspondingly larger travel dimensions compared to the absolute dimension of the movement of the transport element, and in that the sensor device detects these increased travel dimensions.

This measure has the advantage that even relatively small changes in thickness result in relatively large measured length values due to structurally very simple means, so that measured value errors have a relatively small impact. For example, in the case of the aforementioned feed bearing arm, it is very easy to attach mechanical elements, such as gears, parallelograms or the like, to the articulation axis of the feed bearing arm, which allow the feed bearing arm to be pivoted by a small angular range, which with a very small thickness or the hardness of the workpiece to be machined is converted into a relatively large measurable distance.

In a further embodiment of the invention, as seen in the transport direction of the workpieces, a transport element designed as a button is provided at a distance from the feed roller, and the sensor device detects the relative position of the button relative to the guide element.

This measure has the advantage that its presence and its thickness can be determined at a point before the workpiece to be machined is gripped by the feed roller. The feed roller is usually located directly in front of the cutting edge, so that in the case of very fast-working machines in which the deflection of the feed roller is detected, very rapid regulation must take place in order to adapt the machining result to the changed conditions. The button arranged in front of the feed roller allows a change to be detected at an earlier point in time, so that in the meantime in which the workpiece is being transported from the button to the feed roller, the corresponding infeed of the guide element can be carried out, so that then the guide element has already been adjusted accordingly at the point in time at which point of the workpiece with the changing property reaches the feed roller.

This button also opens up the possibility of creating a detection system independently of the feed roller / guide element system, so that, for example, the drive system of the feed roller and cutting device can only be started if the button registers the presence of a workpiece.

In a further embodiment of the invention, the process unit evaluates the measured values obtained from the sensor device with regard to predetermined criteria and is connected via control units to components of the device, in particular to the drive of the feed roller and / or the drive of the cutting device.

This measure has the advantage that the process unit can process the measured values obtained from the sensor device and that appropriate measures are then triggered from these processed measured values via the control units. For example, the sensor device registers that the machining process on a workpiece has ended, i.e. that the transport device has moved towards the knife in its maximum proximity position, the drive of the feed roller and / or the drive of the cutting device can be interrupted or kept at a reduced power level, this state being held until the presence of a sensor device new workpiece to be machined is registered, whereupon the drive of the feed roller and cutting device is switched to full force again.

This makes it possible to save energy between the machining operations by not driving the drives at full load. At the same time, this possibility also opens up to register these partial and full load times, so that a grinding process can then be carried out automatically on the knife, for example after predetermined full load times. This measure also contributes to the automation of the process, so that the operator is no longer based on visual observations of the machining result must infer the current state of the cutting edge of the knife. In addition to activating the drives of the feed roller and cutting device, a certain program sequence can also be triggered on the basis of the measured value obtained, the initial measured value, which, for example, covering a certain thickness, being able to be used as a decision criterion as to which program step or which program sequence is initiated.

In a further embodiment of the invention, the process unit is part of a safety device which is connected to the energy supply and / or the drives and / or a control program unit, and that if limit values are exceeded by the measurement data recorded by the sensor device, safety measures such as "program stop", " Feed roller stop "or" knife drive stop "triggers.

This measure has the advantage that the measured values detected by the sensor device are also used as a safety control variable. If the controlled variable exceeds a certain amount, which can be caused, for example, by foreign bodies getting between the transport element and the guide element, a certain process is initiated in the device. Such foreign bodies can be, for example, body parts such as fingers or a hand of a processing person, articles of clothing of a processing person or foreign bodies adhering to the workpiece. The process triggered by the safety device can be, for example, an optical or acoustic signal, a computer-controlled error diagnosis, an emergency stop with an immediate stop of the entire device, a reduction in the feed rate, a retraction of the guide foot, a program stop, a feed stop, a knife stop or the like. the like.

In a further embodiment of the invention, the measurement data recorded by the sensor device are fed primarily to the safety device.

This measure has the advantage that the safety device can work primarily and also independently of the control circuit which carries out the compensation due to the changes in the material properties or material thickness of the workpieces. The priority of the safety device ensures in every operating state of the device that measures can be initiated immediately if predetermined safety limit values are exceeded.

Further advantages result from the description and the attached drawing.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination but also in other combinations or on their own without departing from the scope of the present invention.

Fig. 1

stark schematisiert und teilweise geschnitten eine Seitenansicht der wesentlichen Bauelemente einer erfindungsgemäßen Einrichtung, die als Schärfmaschine arbeitet;

Fig. 2

eine stark schematisierte Darstellung von lappenartigen Werkstücken, die mit der in Fig. 1 dargestellten Schärfmaschine bearbeitet werden, wobei jeweils ein Zustand vor und nach einem Bearbeitungsvorgang dargestellt ist;

Fig. 3

eine der Fig. 2 entsprechende Darstellung von lappenartigen Werkstücken, die von einer erfindungsgemäßen Einrichtung, die als Spaltmaschine arbeitet, gespalten werden sollen.

Fig. 4

eine erfindungsgemäße Einrichtung, die als Spaltmaschine arbeitet in einem ersten Betriebszustand;

Fig. 5

die Einrichtung von Fig. 4 in einem späteren Betriebszustand; und

Fig. 6

ausschnittsweise und stark vergrößert ein weiteres Ausführungsbeispiel einer erfindungsgemäßen Einrichtung, die als Spaltmaschine arbeitet.

Embodiments of the invention are shown in the drawing and are explained in more detail in the following description. Show it:

Fig. 1

highly schematic and partially sectioned a side view of the essential components of a device according to the invention, which works as a sharpening machine;

Fig. 2

a highly schematic representation of flap-like workpieces that are processed with the sharpening machine shown in Figure 1, each showing a state before and after a machining operation;

Fig. 3

one of FIG. 2 representation of flap-like workpieces that are to be split by a device according to the invention, which works as a splitting machine.

Fig. 4

a device according to the invention, which works as a splitting machine in a first operating state;

Fig. 5

the device of Figure 4 in a later operating state. and

Fig. 6

detail and greatly enlarged another embodiment of a device according to the invention, which works as a splitting machine.

A device 10 according to the invention shown in FIG. 1, which is designed as a sharpening machine, has a cutting device 12, a guide element 14 and a transport element 16.

The cutting device 12 has a bell knife 18 which is connected to a drive 20 which rotates the bell knife 18 about a horizontal axis, as indicated by the arrow 21 in FIG. 1. The bell knife 18 is provided with a cutting edge 22 on its peripheral edge facing away from the drive.

The guide element 14 has a foot 24 which is connected to an actuator 26. The actuator 26 has a threaded spindle 28, via which the foot 24 can be infinitely adjusted, as is shown in FIG. 1 by the double arrow 29.

The transport element 16 has a feed roller 30 which is rotatably mounted on the front end of a feed bearing arm 32 via lateral axle journals 31. The axis of rotation of the feed roller 30 running through the center of the axle journal 31 runs perpendicular to the axis of rotation of the bell knife 18.

The feed bearing arm 32 is pivotally mounted about an axis 34 at a distance from the axle journal 31 of the feed roller 30.

A drive roller 36 of a drive 38 is received on the pivot axis 34 of the feed bearing arm. A belt 40, which rotates the drive roller 36, is connected to a corresponding roller, not shown here, which sits on a lateral journal 31 of the feed roller 30, so that the feed roller 30 is rotated via the drive 38 by means of the belt 40, as is the case here is represented in FIG. 1 by an arrow 41. A compression spring 42, which is supported on a stationary abutment, is connected to the latter in a region between the journal 31 of the feed roller 30 and the pivot axis 34 of the feed bearing arm. The spring 42 gives the feed bearing arm 32 the tendency to move upward in the illustration of FIG. 1, ie in the direction of the foot 24.

The lower right front edge 25 of the foot 24 in the illustration in FIG. 1 lies opposite the highest surface line 33 in the illustration in FIG. 1 of the approximately barrel-like body of the feed roller 30.

The foremost cutting line 23 of the cutting edge 22 is located approximately at the level of an imaginary connecting line between the surface line 33 and the front edge 25 of the foot 24.

A mechanical means 44 in the form of a rod 46, which is part of a sensor device 50, is arranged on the pivot axis 34 or on the corresponding journal of the feed bearing arm 32.

The sensor device 50 has a diode conductor 52 which is arranged in a fixed manner on the device 10 and over which the rod 46 extends at a distance.

The diode conductor 52 detects the respective position of the rod 56 without contact.

In other exemplary embodiments, not shown here, an angle detection by ROD, by potentiometer or by ohmic, inductive or capacitive signals is provided.

The sensor device 50, which can be arranged, for example, on the inside of a housing of the device 10, is connected to a process unit 54. The process unit 54 processes the measurement signals obtained from the sensor device 50, for example by converting by means of an analog-digital converter into digitally detectable values which are then processed by means of a data processing system.

The process unit 54 is connected to the drive 20 of the cutting device 12, to the drive 38 of the feed roller 30 and also to the actuator 26 of the guide element 14.

The device 10 shown in Fig. 1 operates as a sharpening machine, i.e. on a flap-like workpiece 56, for example a leather flap 60, an oblique cut is to be made on the edge surface 62 thereof.

As can be seen from FIG. 2a, the edge surface 62 is processed in such a way that an approximately triangular piece of material is cut off, so that the inclined surface 64 shown in FIG. 2a is formed. A residual edge 63 remains of the edge surface 62 after the machining process. The leather flap 60 is then fed in by means of the guide element 14 and the transport element 16 in such a way that the cutting edge 22 of the bell knife separates a chip 66 from the leather flap 60, the inclined surface then 64 arises. The machined workpiece 56, from which the chip 66 is separated, is then referred to as a blank 65.

The height H (see FIG. 2 on the right side in each case) of the residual edge 63 of the edge surface 62 is determined by the distance between the cutting line 23 and the front edge 25 of the foot 24. The increase in the inclined surface 64 with respect to the flap plane of the leather flap 60 is determined by the inclined position of the guide element 14. In Fig. 1 the foot 24 is shown only very schematically, in other embodiments it does not consist of a rigid metal part, but for example from a roller, the holder of which is pivotable so that the edge surface 62 to be machined in each case in the appropriate or desired angle of Cutting edge 22 is fed.

The process unit 54 contains a program control in which the data for the desired machining result can be entered, whereupon the guide element 26 is moved or pivoted in such a way that the desired sharpening result can be achieved.

As an example, a sharpening result is desired, as shown in Fig. 2a on the right side, i.e. the unprocessed edge surface 62 shown on the left is to be processed in such a way that a residual edge 63 is formed, the height H of which corresponds to half the height of the edge surface 62, the depth T of the inclined surface 64 being assumed to have a certain dimension, which also means that the angle of inclination Inclined surface 64 is determined.

FIG. 1 shows how this sharpening result shown on the right in FIG. 2a can be achieved.

If the thickness of the leather flap 60 now changes, as can be seen in FIG. 1 at the left end of the leather flap 60, the height of the edge surface 62 increases, as shown in FIG. 2b on the left side by the edge surface 62 ' is.

If this thicker area of the leather flap 60 reaches the area between the foot 24 and the feed roller 30, it is deflected downward by a corresponding amount in the illustration in FIG. 1 against the force of the spring 42, as is shown in FIG. 1 by a Arrow 35 is shown. The degree of deflection corresponds to the dimension Δ D, that is, the amount by which the thickness of the leather flap 60 increases. After the deflection, the feed bearing arm 32 and the feed roller 30 assume the position shown in broken lines in FIG. 1. The rod 46 was pivoted by an angular dimension Δ α, which is detected by the sensor device 50.

In Fig. 1, the sensor device 50 is arranged relatively close to the pivot axis 34 of the feed bearing arm 32 by drawing, by appropriately long design of the rod 46 and correspondingly lower arrangement, the rod 46 then sweeps over a relatively large distance, the sensor device 50, so that Even with only small changes in thickness Δ D, relatively large measured values can be detected without large measurement error.

If the foot 24 remains in the unchanged position relative to the cutting line 23, a sharpening result is obtained, as is shown on the right in FIG. 2b. The edge surface 62 ′ which is longer by the thickness dimension Δ D is then machined in such a way that a residual edge 63 with the height H is again formed.

The sloping surface 64 'is considerably longer, i.e. whose depth T 'is much greater. If, however, a sharpening result is to be achieved in which the ratio H: T is constant, this cannot be achieved with a rigid foot 24 not adjusted, since the ratio H: T changes as shown in FIG. 2b on the right 'has changed so that it has become smaller.

Due to the angular displacement Δ α detected by the sensor device 50, which is a function of the displacement path Δ D of the feed roller 30 (a simple geometric function sin α = function Δ D), the process unit 54 makes it simple are calculated by how much the foot 24 or its front edge 25 must be reset so that a residual edge 63 'results, the height H' of which corresponds to half the length of the edge surface 62 '. In the aforementioned embodiment, the foot 24 must be reset by the amount 1/2 Δ D.

If this is the case, the sharpening result shown on the right in Fig. 2c is achieved, i.e. the ratio of H ': T' 'is again approximately the same, whereby H' fulfills the specified condition that the remaining edge 63 'corresponds to half the thickness, that is to say the length dimension of the edge surface 62'.

If another sharpening result is to be achieved, e.g. the depth T should remain unchanged, so the foot is adjusted exactly by the amount of the change in thickness Δ D.

FIG. 3 shows the corresponding problems that occur when splitting a leather cloth 70, the splitting process being carried out using the device 90 shown in FIGS. 4 and 5.

During a splitting process, the leather flap 70 with the thickness D is to be split into two parts along its flap surface, that is to say along its end edge 72, namely in a blank 74 and in a chip 76, which should each have the thickness D / 2. The end edge 72 is fed to a horizontally running band knife, for example the band knife 148 shown in FIG. 6, which, similar to that described in connection with FIG. 1, extends into a gap between a foot of a guide element 144 and a feed roller 150.

If the thickness of the leather flap 70 changes so that it becomes larger and assumes the dimension D ', a splitting result is obtained, as shown in FIG. 3b on the right side. The blank 74 'maintains its absolute dimension, namely D / 2, since this dimension is determined by the distance between the cutting line and the rigid base of the guide element.

As a result, the thickness of the chip 76 'increases.

If the distance between the cutting edge and the guide element is then changed accordingly, as described in connection with FIG. enlarged to dimension D '/ 2, the splitting result shown on the right in Fig. 3c is obtained, i.e. Blank 74 '' and Span 76 '' again have the same thickness, namely D '/ 2.

The device 90 shown in FIGS. 4 and 5 is able to achieve the splitting result shown in FIG. 3c when the thickness D changes in D '.

The device 90 has a cutting device 92, guide elements 94, 95 and transport elements 96, 97.

The cutting device 92 comprises a band knife 98 which runs around two wheels 100, only one wheel 100 being shown here. As described in connection with FIG. 1, the guide element 94 has a foot 104 which is connected to an actuator 106. The actuator 106 has a threaded spindle 108, by means of which the foot 106 can be adjusted continuously, as is shown by an arrow 109.

The transport element 96 has a feed roller 110, the lateral axle journals 111 of which are received in a guide, not shown here, for example an elongated hole guide. The feed roller 110 is rotated by a belt drive 112, as shown by an arrow 113. The axle journals 111 are connected to a stationary supporting spring 114, which gives the feed roller 110 the tendency to move in the direction of the upper cutting edge 102 of the band knife 98 or in the direction of the foot 104. The maximum feed movement is determined by the stop of the slot, whereby care is taken that the feed roller 110 does not hit the cutting edge 102.

The guide element 95 consists of a plate 116, over which a leather flap 70 can be moved flat. A button 118 has an arm 120 which can be pivoted about an axis 119 and at the front end of which a roller 122 is provided, which lies in the position of the button 118 on the plate 116 shown in FIG. 4. The button 118 is pressed against the plate 116 by a spring, not shown here. On the side of the axis 119 opposite the arm 120, the button 118 is provided with a mechanical means 124 in the form of a rod 125 which extends in a straight line to the arm 120.

The rod 125 is part of a sensor device 130 which detects the respective pivoting position of the rod 125.

The sensor device is connected to a process unit 134, which in turn is connected to the drive 112 of the feed roller and the actuator 106 of the foot 104.

In the position shown in Fig. 4, the button is in its zero position, i.e. Via the sensor device, the process unit 134 is informed of the state in which there is no leather cloth 70 in the device 90. It can now be provided to use this signal to either stop the drive of the feed roller 110 and also the drive of the band knife or to run on reduced load operation.

If a leather flap 70 is now supplied, as indicated by arrow 117 in FIG. 4, the leather flap 70 having the thickness D, the arm 120 of the push button 118 is pivoted away from the plate 116, as indicated by an arrow 121 is indicated. The roller 122 then runs on the outer surface of the leather flap 70, which lies opposite the surface over which the leather flap 70 slides on the plate 95. The pivoting detected by the sensor device 30, which then again provides information about the dimension D, the thickness of the leather flap 70, is processed by the process unit 134 and the foot 104 is then delivered such that the distance between the cutting line of the cutting edge 102 of the band knife 98 and the foot is 104 D '/ 2. The splitting result shown on the right in FIG. 3a can then be achieved, as can also be seen in FIG. 5 on the right.

If the thickness dimension of the leather flap 70 increases, as can be seen on FIG. 5 on the left-hand side, that is to say the thickness D increases to the thickness D ', the arm 120 of the button 118 is pivoted a corresponding amount, which is in turn registered by the sensor device 130. The position of the button 118 shown in broken lines in FIG. 5 corresponds to the position as the button has assumed in the region of the thickness D of the leather tab 70. The change in thickness is registered by the process unit 134 and, as previously mentioned, the foot 104 is reset by half the amount of the change in thickness, as indicated by the arrow 134 in FIG. 5. In this case, the splitting result desired in FIG. 3c on the right-hand side can then be achieved, ie that blank 74 ″ and chip 76 ″ have the same thickness.

It is also possible to keep the feed roller 110 shown in FIGS. 4 and 5 pivotable via an arm, in accordance with the embodiment of FIG. 1.

6 shows a further exemplary embodiment of a device 140 according to the invention, which, as already mentioned, has a feed roller 150 and an adjustable foot 144, so that a leather flap 80 transported between them is fed to a band knife 148 so that a splitting process is carried out can lead to a blank 82 and a chip 84.

In this embodiment, a sensor device 160 directly detects the deflection of the axis of rotation 151 of the feed roller 150.

The position of the axis of rotation 151 of the feed roller 150 designated NL (normal position) in FIG. 6 corresponds to a normal position for the processing of the leather cloth 80. If a foreign object 86 is now also drawn into the gap between the foot 144 and the feed roller 150, the feed roller 150 or their axis 151 by a large amount, shifted downward in the illustration in FIG. 6, which corresponds to the thickness DF of the foreign body. The Foreign objects 86 can be, for example, a piece of clothing or a body part of the operator of the device 140, or else foreign objects that adhere to the leather tab 80. If the deflection of the axis 150 exceeds a dimension SW (threshold value), this is immediately registered by the process unit connected to the sensor device 160 and immediate measures such as "drive stop" or "machine off" are initiated via a safety device. If a threshold value is exceeded, the adjustment mechanism of the foot 144 described above is not triggered, but the appropriate safety measures are taken via the safety device with priority. The threshold value can be determined by entering the expected fluctuation ranges of the thicknesses of leather flaps 80 to be processed, which are in a certain range. If this dimension is exceeded, it can no longer be a matter of a change in the thickness of the leather flap 80 to be processed, but foreign or other interfering bodies must have been drawn in.

Claims (11)

Device for processing flap-like workpieces (56, 60, 70, 80), in particular made of leather or leather substitute or other materials, with a cutting device (12, 92) having a knife (18, 98, 148), by means of which sharpening or Splitting operations are carried out on the workpieces (56, 60, 70, 80) with at least one guide element (14, 94, 95, 144) and at least one transport element (16, 96, 97) that can be moved against a force and that is moved by the force the tendency is given to move in the direction of the guide element (14, 94, 95, 144), the workpieces (56, 60, 70, 80) between the guide element (14, 94, 95, 144) and the transport element (16, 96 , 97), in contact with them, are fed to the knife (18, 98, 148), characterized in that a sensor device (50, 130, 160) is provided which detects the respective relative position between the guide element (14, 94, 95, 144) and movable transport element (16, 96, 97). Device according to claim 1, characterized in that the sensor device (50, 130, 160) is connected to a process unit (54, 134) which converts the measurement signal received from the sensor device (50, 130, 160) into a control signal. Device according to claim 2, characterized in that the process unit (54, 134) with an actuator (26, 103) of a guide element (14, 94) arranged directly in front of the knife (18, 98) as seen in the transport direction of the workpieces (56, 70) ), and this guide element (14, 94) during the machining of a workpiece (56, 70) in dependence on the measurement signal of the sensor device (50, 130). Device according to one of claims 1 to 3, characterized in that the sensor device (50, 30, 160) detects the position or change in position of the transport element (16, 96, 97) without contact. Device according to one of claims 1 to 4, characterized in that the transport element (16, 96), as known per se, is designed as a driven feed roller (30, 110). Device according to claim 5, characterized in that the feed roller (30) is carried by a feed bearing arm (32) which can be pivoted about an axis (34), and in that the sensor device (50) detects the change in angle of rotation Δ α or a linear moment of movement thereof of the feed bearing arm ( 32) recorded. Device according to one of claims 1 to 6, characterized in that mechanical means (44, 124) are provided which result in correspondingly larger travel dimensions compared to the absolute dimension of the movement of the transport element (16, 96), and in that the sensor device (50, 130) these increased distances measured. Device according to one of Claims 5 to 7, characterized in that a transport element (97) which is designed as a button (118) and is at a distance from the feed roller (110), as seen in the transport direction of the workpieces (70), and that the sensor device ( 130) detects the relative position of the button (118) relative to the guide element (95). Device according to one of claims 5 to 8, characterized in that the process unit (54, 134) evaluates the measured values obtained from the sensor device (50, 130) with regard to predetermined criteria, and in that the process unit uses control units to supply the components with energy Device, in particular the drive (20, 112) of the feed roller (30, 110) and / or the drive (20) of the cutting device (12) is connected. Device according to one of Claims 2 to 9, characterized in that the process unit (54, 134) is part of a safety device which is connected to the energy supply and / or the drive units and / or a control programming unit, and if the sensor device ( 50, 130, 160), the measured data triggers safety measures such as "program stop", "feed roller stop" or "knife drive stop". Device according to Claim 10, characterized in that the measurement data recorded by the sensor device (50, 130, 160) are fed primarily to the safety device.

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