EP3525950A1 - Backgauge for a bending machine and method for positioning a backgauge of this kind - Google Patents

Abstract

The invention relates to a backgauge (15) for a backgauge positioning system of a bending machine. The backgauge (15) comprises a stop finger (18) on which at least one stop surface (17) is formed and a base unit (21) designed for coupling to the backgauge positioning system (14), wherein the stop finger (18) is coupled to the base unit (21) by means of a linear guide (29) and the stop finger (18) can be displaced relative to the base unit (21) between a pushed-forward working position (28) and a retracted position (30), characterised in that the stop finger (18) and the base unit (21) are coupled to a first spring element (34), by means of which the stop finger (18) is prestressed in its working position (28), and in that a locking device (41) is formed by means of which the stop finger (18) can be optionally locked in the working position (28) or is released for displacement, counter to the spring force of the first spring element (34), into its retracted position (30).

Description

 REAR BELL FOR A BENDING MACHINE AND

 METHOD FOR POSITIONING SUCH A REAR BUMPER

The invention relates to a backgauge for a Hinteranschlagpositioniersystem a bending machine, and a method for positioning the backgauge.

From DE 3739949 Cl a backgauge for a plate bending machine is known, in which a stop finger is displaceable relative to a base unit. The stop finger can be locked by means of a locking pin, which can be moved into a corresponding hole in a guide rail.

The known from DE 3739949 Cl backgauge has the disadvantage that upon activation of the safety function of the stop finger, the automatic operation of the stop finger is limited available.

From EP 2 915 604 AI a backgauge is known in which a stopper finger is displaceable relative to a base unit when a predetermined force is exceeded and thereby solves a magnetic fixation. The known from EP 2 915 604 AI backgauge has the disadvantage that the predetermined force for releasing the magnetic fixation must be chosen to be correspondingly low in order to ensure the maintenance of the safety function. However, the necessarily weak dimensioning of the magnetic fixation can cause it to be solved unintentionally when attacking sheet metal workpieces.

The object of the present invention was to overcome the disadvantages of the prior art and to provide an apparatus and a method by means of which a backgauge can be positioned with increased safety, while retaining the full functionality of the backgauge.

This object is achieved by an apparatus and a method according to the claims. According to the invention, a backgauge is formed for a backgauge positioner system of a bending machine. The backgauge comprises an abutment finger on which at least one abutment surface is formed, a base unit which is designed for coupling to the backstop positioner system, wherein the abutment finger is coupled to the base unit by means of a linear guide and the abutment finger is coupled relative to the base unit between a forwardly displaced working position and a retraction position is displaceable. The stop finger and the base unit are coupled to a rear part device, in particular a first spring element, by means of which the stop finger is biased into its working position. Furthermore, a switchable locking device is formed, by means of which the stop finger is optionally locked in the working position or released for displacement, in particular against the spring force of the first spring element, in its retracted position.

An advantage of the inventive design of the back gauge is that the stop finger is biased by the first spring element in its working position.

As a result, it can be achieved that the stop finger is moved back into its position after being displaced from its working position as soon as an impact force causing the displacement is removed again. Furthermore, the stop finger can be locked by means of the locking device either in its working position or released for displacement against the spring force of the first spring element. In particular, a stop mode can be realized by the locking device, in which the stop finger is locked in its working position and thus formed to stop bending sheet metal workpieces. When the locking device is deactivated, the backgauge is in a so-called safety mode or travel mode in which the stopper finger can be moved relative to the base unit, wherein only the spring force of the first spring element must be overcome. The spring force of the first spring element is chosen to be correspondingly low, since in a movement of the back gauge in addition to the spring force of the first spring element, the inertia of the stop finger acts on the obstacle.

Furthermore, it may be expedient if the locking device comprises a holding part, in particular an electromagnet, wherein the stop finger can be locked relative to the base unit by applying activation energy in the holding part. The advantage here is that an electromagnet can be easily activated or deactivated in an automated bending machine. In addition, electricity is present as an energy source for the electromagnet on each bending machine. Compared to a mechanical locking system, an electromagnet also has the advantage that no mechanically displaceable components are formed, which are subject to wear or must be maintained. Thus, an electromagnet can have an increased life.

In addition, it can be provided that the locking device has a mechanically acting locking. The stop finger can be fixed in its position relative to the base unit by means of the mechanically acting locking unit.

In a first exemplary embodiment, it may be provided, for example, that the mechanically acting locking unit of the locking device is designed to produce a positive connection between the stop finger and the base unit. Such a form-fitting connection can be achieved, for example, by means of a shaped element which is arranged on the basic unit and which is inserted into a corresponding recess of the stop finger.

In particular, it can be provided that the mold element has a wedge surface. It can thereby be achieved that the positioning accuracy of the back stop unit can be increased, since the stop finger can be pressed by the wedge surface into its working position.

Alternatively, it can be provided that the shaped element can be designed, for example, in the form of a passport. Such a dowel pin may for example also have a conical shape in order to achieve an exact positioning of the stop finger can.

The mold element can be inserted by means of various trained actuators in the recess of the stop finger. The actuators can be designed, for example, in the form of pneumatic or hydraulic cylinders, electric linear or rotary drives or electromagnets. In an alternative variant, it can be provided that the mechanically acting locking unit comprises a clamping device and not a form-fitting, but a frictional connection is made. Of course, it is also conceivable that the positive connection can be made by means of a micro-toothing.

Furthermore, it can be provided that a second spring element is formed, which is coupled with the interposition of the locking device with the stop finger and the base unit, wherein when the locking device of the stop finger is fixed by means of the second spring element in its working position. The advantage here is that when locking the locking device of the stop finger is not completely rigidly coupled to the base unit, but that the stop finger is biased in addition to the spring force of the first spring element with the spring force of the second spring element in its working position. As a result, the stop finger can be displaced out of its working position against the action of the two spring elements with an excessively large acting force. This allows a protection of the entire Hinteranschlageinheit. Another advantage is that force peaks, caused by harder hit the sheet to the stop finger are partially absorbed by the spring. The second spring element can be interposed in all different types of locking devices.

In addition, it can be provided that the second spring element has a greater spring stiffness than the first spring element and / or that the second spring element has a greater pretension than the first spring element. The advantage here is that the stop finger is biased by means of the first spring element only by a small application of force in its working position and that selective connection of the second spring element, the bias of the stop finger can be increased in its working position by a multiple. The first spring element may, for example, have a spring stiffness between 0.01 N / mm and 1 N / mm, in particular between 0.1 N / mm and 0.5 N / mm, preferably approximately 0.2 N / mm. In addition, the first spring element may have a pretension between 1 N and 15 N, in particular between 3 N and 10 N, preferably approximately 7 N. The second spring element may for example have a spring stiffness between 0.1 N / mm and 30 N / mm, in particular between 1 N / mm and 10 N / mm, preferably in about 2 N / mm. In addition, the first spring element may have a preload between 20 N and 600 N, in particular between 160 N and 450 N, preferably in about 250 N to 300 N.

Also advantageous is an embodiment according to which it can be provided that the retaining part of the locking device is held immovably relative to the base unit in the main adjustment direction and that the locking device has a counter element interacting with the retaining part, which is arranged on a guide rod, wherein the Guide rod is mounted at least on a first bearing jaws, wherein the counter-element is arranged at an end region of the guide rod and the second spring element is arranged with respect to the first bearing jaws opposite to the counter-element on the guide rod.

Alternatively, it may also be provided that the electromagnet is held immovably relative to the base unit and that the locking device has a cooperating with the electromagnet counter element which is arranged on a guide rod, wherein the guide rod is mounted on a first bearing jaws and on a second bearing jaws , which are arranged at a distance from each other, wherein the

Counterelement according to a flying bearing the first bearing jaws closer to a lying outside the two bearing jaws end portion of the guide rod is arranged. By this construction of the back gauge, the functionality of the optionally lockable stop finger can be implemented as efficiently as possible, the overall structure of the back gauge is designed as simple as possible.

Furthermore, it may be useful if the guide rod is mounted with a bearing clearance in the first bearing jaws, so that a slight angular rotation and / or radial displacement between the guide rod and the first bearing jaws is possible.

Furthermore, it can be provided that the guide rod is additionally mounted on a second bearing jaws, wherein the first bearing jaws and the second bearing jaws are arranged at a distance from one another. According to a development, it is possible that a stop element for the second spring element is formed on the guide rod, wherein the second spring element is designed as a compression spring and is received between the first bearing jaw and the stop element on the guide rod, whereby the stop element by means of the second Spring element away from the first bearing jaws and thus the counter-element is biased towards the first bearing jaws out. By this measure, the second spring element can be positioned as easily as possible in the backgauge. In addition, the stop finger can be biased in its working position.

Furthermore, it can be provided that the holding part is designed as an electromagnet and the counter element is designed as cooperating with the electromagnet disc, which is arranged on the front side of the guide rod, wherein the electromagnet and the counter element abut contact surfaces against each other. The advantage here is that such a connection can be switched with a very short switching time.

Furthermore, it can be provided that the electromagnet and / or the counter-element are received on a joint bearing, so that the contact surfaces are aligned parallel to each other. The advantage here is that by this measure the air gap between the two contact surfaces can be reduced and thereby the holding force of the magnet can be increased.

In a further development it can be provided that the joint bearing comprises a universal joint or a ball joint. The advantage here is that such joint bearings are easy to manufacture and also have a high resistance.

Furthermore, it may be expedient if a buffer element is formed, which serves to damp the stop finger during the process in the retracted position. The advantage here is that this measure protects the backgauge.

In addition, it can be provided that the linear guide is designed in the form of a recirculating ball guide. A recirculating ball guide has the advantage that it as possible is smooth and therefore the spring force of the first spring element can be chosen as low as possible.

Furthermore, it can be provided that the linear guide comprises a guide carriage, which is rather coupled to the stop finger and comprises a guide rail, which is coupled to the base unit.

According to a particular embodiment, it is possible for the base unit to have a base part which is coupled to the rear stop positioning system and has a lid part which is fastened to the base part by means of fastening means. By this measure it can be achieved that the backgauge can be easily assembled or simply disassembled for maintenance.

According to an advantageous development, it can be provided that the two bearing jaws are fastened to the cover part. The advantage here is that the bearing jaws are easily accessible by this measure.

In particular, it may be advantageous if the guide rail is fastened to the cover part. Furthermore, it can be provided that two of the second spring elements are arranged parallel to one another. This has the advantage that the bias of the stop finger can be increased to its working position, wherein the individual second spring elements do not have to have an excessively high spring stiffness, but the spring stiffness of the two second spring elements is added. This can save weight.

In addition, it can be provided that a force sensor is formed, which is designed to detect the magnitude of an action force. By this measure, the abutment force of a sheet metal workpiece to be struck can be detected. This makes it possible to signal the machine operator when the sheet metal workpiece with a predefined abutment force abuts the stop finger and thus correct positioning of the sheet metal workpiece is reached. Also advantageous is an embodiment, according to which it can be provided that the first bearing jaws of the abutment surface is arranged closer than the second bearing jaws.

According to a development, it is possible that at least one indicator element is arranged on the stop finger for indicating the state of the locking device. The advantage here is that the operator of the state of the locking device can be displayed by the display element and the machine operator gets notified whether the bending machine is ready to strike the sheet metal workpiece to be bent. Furthermore, it may be expedient if a sensor element is formed, which serves to detect a relative movement and / or relative position between the stop finger and the base unit. The advantage here is that by this measure a displacement of the stop finger relative to the base unit can be detected and thereby a movement of the back gauge can be stopped in time.

In addition, it can be provided that the sensor element is designed in the form of an inductive sensor. In particular, an inductive sensor has a high detection accuracy and a short detection time. According to the invention, a method is provided for positioning the backgauge by means of a rear stop positioning system of a bending machine. The method comprises the following method steps:

 - Setting a travel mode of the backgauge, wherein the locking device is not locked and wherein the stop finger is biased by means of a rear part device, in particular a first spring element in its working position;

 - Method of back gauge by means of the Hinteranschlagpositioniersystem in its predetermined stop position;

- Arrest the stop finger in its working position by means of the locking device. An advantage of the method according to the invention is that when positioning the back stop a so-called travel mode or safety mode can be set, in which the stop finger is displaceable relative to the base unit. This allows the stop finger to touch an obstacle, such as the hand of a machine operator move relative to the base unit so as not to injure the operator. The displacement is chosen in particular so large that when detecting the touch of the stop finger on the obstacle, the movement of the back gauge can be stopped within this displacement.

According to a particular embodiment, it is possible that during the travel mode of the back gauge by means of the sensor element, the relative movement and / or relative position between the stop finger and the base unit is monitored and upon detection of a relative movement between the stop finger and the base unit during the process of back gauge, the movement is stopped abruptly. The advantage here is that by this measure the necessary displacement of the stop finger relative to the base unit can be kept as low as possible.

For a better understanding of the invention, this will be explained in more detail with reference to the following figures.

In each case, in a highly simplified, schematic representation:

Fig. 1 is a perspective view of an embodiment of a bending machine;

2 is a perspective view of an embodiment of a backgauge in a view obliquely from above.

3 is a perspective view of an embodiment of a backgauge in a view obliquely from below;

Figure 4 is a sectional view of the back gauge in a first sectional plane, wherein the stop finger is in the working position.

Figure 5 is a sectional view of the back gauge in the first sectional plane, wherein the stop finger is in the retracted position and the locking device is not activated. a sectional view of the back gauge in the first sectional plane, wherein the stopper finger is in the retracted position and the locking device is activated; a sectional view of the back gauge in a second sectional plane, wherein the stop finger is in the retracted position and the locking device is not activated; a perspective view of another embodiment of the backgauge with only a first bearing jaws; a schematic sectional view of another embodiment of the back gauge with only a first bearing jaws and a guide rod which is equipped with a ball joint; a schematic sectional view of another embodiment of the backgauge with a form-fitting engaging retaining element; a schematic sectional view of another embodiment of the backgauge with a holding element in the form of a pneumatic cylinder.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component designations, wherein the disclosures contained in the entire description can be mutatis mutandis to the same parts with the same reference numerals or component names. Also, the location information chosen in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and these position information in a change in position mutatis mutandis to transfer to the new location.

Hereinafter, a workpiece processing machine, and a method for operating a workpiece processing machine using a bending machine or press brake as Embodiment described in detail. It should be noted that the following details are of course also applicable to other types of workpiece processing machines in which automated controlled stop devices are used with stop fingers for positioning workpieces, or that a person skilled in the art of the following description can also apply to other types of workpiece processing machines to be taken.

1 shows an embodiment of a workpiece processing machine 1 in the form of a bending machine 2, in particular a press brake 3 shown. The workpiece processing machine 1 or press brake 3 is provided for processing, in particular for bending a workpiece 4. The press brake 3 has a perpendicular to a footprint 5 aligned, fixed table bar 6. For machining workpieces 4, the bending machine 2 or the illustrated press brake 3 comprises a pressing beam 7, which is adjustable or movable relative to the table beam 6 in the vertical direction by means of drive means 8, for example hydraulic cylinders 9.

The machining or forming of a workpiece 4 is accomplished in the press brake 3 according to the embodiment shown in FIG. 1 by means of a lower bending tool 10 and an upper bending tool 11. In this case, the lower bending tool 10, for example a so-called bending die, can be arranged in a lower tool receptacle 12 of the table beam 6. An upper bending tool 11 or a so-called bending punch can be arranged in an upper tool holder 13 of the pressing beam 7.

Usually, the bending tools 10, 11 are interchangeably arranged and held in the tool holders 12, 13 so that suitable bending tools 10, 11 can be selected or used for a respective machining or forming of a workpiece 4. Of course, it is also possible that in each case a plurality of lower bending tools 10 and upper bending tools 11 are arranged in the operation of the press brake 3 in the tool holders, for example, in order to make 4 different bending operations in successive forming or bending operations on a workpiece. For reasons of clarity, only one lower bending tool 10 and one upper bending tool 11 are shown in the exemplary embodiment according to FIG. 1. In the case of the press brake 3 illustrated as an exemplary embodiment in FIG. 1, at least one automatically controlled backgauge positioning system 14 with at least one back stop 15 for positioning the workpiece 4 is also shown. The backgauge 15 is shown only schematically and will be described or illustrated in more detail in the other figures.

In the exemplary embodiment shown, two backgauge positioning systems 14, each having a backgauge 15, are shown by way of example. The Hinteranschlagpositioniersy systems 14 shown in FIG. 1 or Hinteranschläge 15 are arranged in a free space at a rear side of the table beam 6 of the bending machine 2. The one or more back stops 15 can each be adjusted or moved in a provided for positioning a workpiece 4 stop position 16. If a backgauge 15 is adjusted to a stop position 16, a workpiece 4 to be machined can then be applied to a stop face 17 of a stop finger 18 of the back stop 15 from a front side pointing away from the press room or a workpiece feed side of the workpiece processing machine 1. Thereby, the workpiece 4 can be positioned in a desired position between the two bending tools 10, 11 in order to be able to perform a bending operation at a desired position.

The stop fingers 18 shown by way of example in FIG. 1 have only one stop surface 17. In principle, embodiments of stop fingers 18 may also include more than one stop surface 17, as well as additional bearing surfaces for workpieces 4.

The Hinteranschlagpositioniersysteme 14 or backgauges 15 shown in FIG. 1 are usually adjusted or moved by means of drive not shown in detail. The drive arrangements can include, for example, guideways, as well as actuators such as electric motors, in particular servomotors, and are driven automatically.

To control the movement or adjustment movements of the backgauge positioning system 14 or the back gauge 15, a control device 19 may be provided. As 1, the control device 19 may comprise a plurality of components, for example a plurality of processors or computer components, input means for inputting control commands, output means for displaying information, etc. Furthermore, it is also possible that the control device 19 further control components is connected, for example, with mobile input and output means via a network, or via the Internet.

In bending machines 2, an adjustment or an automated method of the back stops 15 along at least one Hauptverstellrichtung 20 may be provided. In addition, the back stops 15 can also be adjusted automatically in the longitudinal direction of the bending machine 2 or with respect to its height.

Basically, there is a risk of Kollisio- nen of the stop finger 18 with other objects, such as a hand of an operator in automatically controlled Verfahr- or adjustment movements of the Hinteranschlagpositioniersystems 14 and the back stop. Therefore, the backgauge 15, as described in more detail in the other figures equipped with a safety function to protect the operator.

In Figures 2 and 3, the backgauge 15 is shown in a perspective view obliquely from above or obliquely from below. In FIGS. 4 to 6, the back stop 15 is shown cut in a first sectional plane, wherein different positions of the back stop 15 are shown. In Figures 7 and 8, the backgauge 15 is shown in further sectional views. For identical parts, the same reference numerals or component designations are used as in the respective preceding figures. In order to avoid unnecessary repetition, reference is made in each case to the detailed description in the preceding figures, wherein the following description is based on the illustration in FIGS. 2 to 8.

The backgauge 15 has a stop finger 18 and a base unit 21. The stop finger 18 is displaceable relative to the base unit 21 in the main adjustment direction 20 this added. The base unit 21 has a coupling device 22, by means of which the back gauge 15 is attached to the backgauge positioning system 14.

As can be seen from FIGS. 2 and 3, it can be provided that the base unit 21 has a base part 23 on which a cover part 24 is arranged. The coupling device 22 is preferably arranged on the base part 23 of the basic unit 21. The cover part 24 can be arranged on the base part 23 of the basic unit 21 by means of fastening means 25, in particular screws. As is further apparent from FIGS. 2 and 3, it can be provided that the stop finger 18 has an exchangeable fingertip 26 on which the stop surface 17 is formed. The stop surface 17 is preferably arranged at right angles to the main adjustment direction 20. In addition, it can also be provided that various recesses 27 are formed, which likewise have a stop surface 17.

4-6, the Hinteranschlageinheit 15 is shown in various positions, wherein in all three figures 4-6 a sectional view was selected with the same cutting plane. In the sectional view, the cover part 24 has also been shown in an exploded view to better represent and describe the function of the back gauge 15. The following description is based on a synopsis of FIGS. 4-6.

In the illustration of Fig. 4, the stop finger 18 is in its advanced working position 28, which may also be referred to as a basic position. As can be seen from FIG. 4, a linear guide 29 is formed, by means of which the stop finger 18 is displaceably received on the basic unit 21. By means of the linear guide 29 of the stop finger 18 between the pushed forward working position 28 and a pushed back retraction position 30 is displaceable. The linear guide 29 is designed such that the stop finger 18 relative to the base unit 21 in the Hauptverstellrichtung 20 between the working position 28 and the retracted position 30 is displaceable.

Preferably, the linear guide 29 comprises a guide carriage 31 which is slidably received in the main adjustment direction 20 on a guide rail 32. The guide carriage 31 may be mounted on the guide rail 32 by means of a recirculating ball bearing.

Alternatively, it is also conceivable that between the guide carriage 31 and the guide rail 32, a sliding bearing, such as a dovetail guide is formed.

As is further apparent from FIG. 4, it can be provided that two of the guide carriages 31 are formed and are arranged at a distance 33 from each other. The formation of two guide carriages 31 has the advantage that the stop finger 18 can be stressed with an increased force, in particular an increased bending load.

In addition, a first spring element 34 is provided, by means of which the stop finger 18 is biased into its working position 28. The first spring element 34 is designed in particular as a compression spring and arranged between an end face 35 of the stop finger 18 and an end face 36 of the basic unit 21. Instead of the first spring element 34, a further rear part device, such as a pneumatic cylinder, a gas spring, an electric linear drive and the like may be provided. Furthermore, it can be provided that a guide pin 37 is formed, on which the first spring element 34 is accommodated. The guide pin 37 may be rigidly coupled to the stop finger 18, or be included on this. Furthermore, it can be provided that on the base unit 21, a stop bar 38 is formed, on which the end face 36 is formed for abutment of the first spring element 34.

On the stop bar 38, a passage 39 may be formed, through which the guide pin 37 is passed. On the side opposite the first spring element 34 side of the stop bar 38, a securing ring 40, in particular an axial securing ring, may be arranged on the guide pin 37. By means of the securing ring 40, the stop finger 18 can be held in its working position 28, wherein in the working position 28 of the stop finger 18 the securing ring 40 rests against the stop bar 38. Furthermore, a locking device 41 is formed, by means of which the stop finger 18 is fixable in its working position 28. The locking device 41 may include a holding part 42 a, which cooperates with a counter element 43. In the present embodiment it can be provided that the holding part 42a is formed in the form of an electromagnet 42b.

In particular, it can be provided that the electromagnet 42b is accommodated on a magnet holder 44. The magnet holder 44 can be coupled by means of fastening means 45, in particular screws, with the cover part 24 of the basic unit 21. In other words, it can be provided that the electromagnet 42b is received rigidly or non-displaceably on the basic unit 21.

The counter element 43, however, is motion-coupled with the stop finger 18. In particular, it can be provided that the counter element 43 is embodied in the form of a magnet, which cooperates with the electromagnet 42b.

Furthermore, it can be provided that the counter element 43 is received on a guide rod 46, wherein the guide rod 46 is slidably received on a first bearing jaws 47 and on a second bearing jaws 48 in Hauptverstellrichtung 20. The first bearing jaw 47 and the second bearing jaw 48 are arranged at a distance 49 from each other and secured to the stop finger 18.

The counter element 43 is preferably arranged on an end region 50 of the guide rod 46. The end region 50 of the guide rod 46 projects freely with respect to the first bearing block 47.

Furthermore, it can be provided that a second spring element 51 is arranged on the guide rod 46 between the first bearing jaw 47 and the second bearing jaw 48. The second spring element 51 may in particular be designed as a compression spring and abut the first bearing bar 47 as well as a stop element 52 which is arranged on the guide rod 46. Due to the spring force of the second spring element 51, the stop element 52, which is arranged between the first bearing jaw 47 and the second bearing jaw 48, is pressed in the direction of the second bearing jaw 48. This will also do that Counter-element 43 is pressed in the direction of the second bearing jaws 48 and the first bearing jaws 47. In other words, both the first bearing jaw 47 and the second bearing jaw 48, which are coupled by means of fastening means 53 with the stop finger 18, are urged toward the counter element 43 by the second spring element 51.

If now the solenoid 42 b is energized and thus unfolds its magnetic action and the counter element 43 adheres to the solenoid 42 b, the stop finger 18 is biased by the force of the second spring element 51 and the force of the first spring element 34 in the working position 28 pressed into this.

Now, if an action force 54, applied by the workpiece 4, acts on the stop surface 17 and the solenoid 42b is activated, the second spring element 51 and the first spring element 34 counteract the action force 54. If the spring force of the two spring elements is less than the contact force 54, the stop finger 18 together with the two bearing jaws 47, 48 arranged thereon are pressed in the direction of retraction position 30 and thus displaced relative to the guide rod 46, since the counter element 43 adheres to the electromagnet 42b.

Such a shifted position is shown in Fig. 6. This shift occurs when the contact force 54 is greater than a maximum permissible contact force, whereby the backgauge 15 would be damaged. Due to the possibility of displacement of the stop finger 18 against the force of the second spring element 51, force peaks, which occur due to impacts when striking large workpieces 4, can be intercepted. Furthermore, it may be provided that a buffer element 55 is formed, which is arranged between the stop finger 18 and the stop bar 38 and is designed to buffer a shock.

When the electromagnet 42b is deactivated, the counter element 43 does not adhere to the electromagnet 42b and thus the second spring element 51 no longer acts against the displacement of the stop finger 18, if in this state the acting force 54 is, for example by the hand of a machine operator is greater than the low spring force of the first spring element 34, the stop finger 18 can be moved relative to the base unit 21, as shown in Fig. 5. If the contact force 54 is now removed again, then the stop finger 18 shifts by the spring force of the first spring element 34 back to its working position 28. A displacement 56 of the stop finger 18 between the working position 28 and the retraction position 30 is preferably chosen so large that at a predetermined travel speed of the back gauge 15 in Hauptverstellrichtung 20 and impact of the stopper finger 18 at an obstacle enough travel remains to slow the Hinteran- schlagpositioniersy system 14 with a maximum allowable acceleration.

Furthermore, it can be provided that a sensor element 57 is arranged on the back stop 15, by means of which a relative movement between the stop finger 18 and the base unit 21 or a relative position between the stop finger 18 and the base unit 21 can be detected. By means of the sensor element 57, the control device 19 can be signaled a collision with an object.

From FIG. 7 it can be seen that the guide rail 32 of the linear guide 29 is coupled to the cover part 24 of the basic unit 21.

From Fig. 8 it can be seen that it can be provided that in the rear stop 15 two of the second spring elements 51 are formed. Furthermore, it can be provided that between a second end portion 58 of the guide rod 46 and a rear wall 59 of the stop finger 18, a force sensor 60 is arranged, which is designed to detect the biasing force of the second spring element 51. When the solenoid 42b is activated and the mating member 43 adheres to the solenoid 42b, the force measured at the force sensor 60 is the force of the second spring member 51 less the engagement force 54 decreased by the force of the first spring member 34. If now the acting force 54 is equal to the spring force of the first spring element 34 and the second spring element 51, then a force of zero magnitude is measured on the force sensor 60. If the contact force 54 is further increased, the guide rod 46 completely lifts off from the force sensor 60 and the force sensor 60 continues to measure the force zero.

On the stop finger 18, in particular on the stop surface 17, a display element 61 are formed, by means of which the activation of the locking device 41 can be displayed. The display element 61 may be formed, for example, in the form of LED displays. Furthermore, it can be provided that the action force 54 is determined by means of the force sensor 60, and this is likewise indicated on the display element 61 when the action force 54 is reached in a predetermined force range.

In a special bending mode for bending particularly thin or particularly large workpieces 4, provision may be made for the backgauge 15 to be designed to pick up the workpiece 4. This can be realized in particular by moving the back stop 15 as far as possible to the table beam 6 in order to insert the workpiece 4. Subsequently, the workpiece 4 is placed on the back gauge 15 and pressed against the stop surface 17. By means of the force sensor, the contact force 54 is detected on the stop surface 17, and subsequently the back stop 15 moved away from the table bar 6 in its stop position 16, wherein the workpiece 4 constantly rests on the back gauge 15 and thereby excessive bending of the workpiece 4 is held back.

FIG. 8 shows in a perspective view a further possible construction of the back gauge 15, again using the same reference numerals or component designations for the same parts as in the preceding FIGS. 1 to 7. To avoid unnecessary repetition, reference is made to the detailed description in the preceding figures 1 to 7 or reference.

As can be seen from FIG. 8, provision can be made for the guide rail 32 to be arranged on the base unit 21 of the rear stop 15 and for the stop finger 18 to be accommodated displaceably relative to the base unit 21 by means of the guide carriage 31. Furthermore, the first spring element 34 is shown schematically, which biases the stop finger 18 in its working position 28. In addition, the first bearing jaws 47 with the Stop finger 18 is coupled and is displaceable together with this. In the first bearing jaw 47, the guide rod 46 is accommodated, which is displaceable relative to the first bearing jaw 47. At one end portion of the guide rod 46, the stopper member 52 is formed. The second spring element 51 is received or prestressed between the first bearing jaw 47 and the stop element 52. By the second spring element 51, the stop element 52 is pushed away from the first bearing jaw 47. On the opposite side of the first bearing jaw 47 to the stop element 52, the counter element 43 is coupled to the guide rod 46. The counter element 43 cooperates with the electromagnet 42 b, which is coupled to the base unit 21.

As can be seen from FIG. 8, it can be provided that, in the fixed state of the back stop 15, a contact surface 62 of the electromagnet 42b interacts with a contact surface 63 of the counter element 43. In order to achieve that the two contact surfaces 62, 63 rest against each other as much as possible, it can be provided that the counter element 43 is coupled to the guide rod 46 via a joint bearing 64. As a result, the two contact surfaces 62, 63 can be aligned parallel to one another. As can be seen from FIG. 8, it can be provided that the joint bearing 64 is designed in the form of a universal joint.

Such a trained universal joint or joint bearing 64 can of course be used not only for receiving the counter element 43, but it is also possible that the joint bearing 64 is adapted to receive the electromagnet 42 b and between the electromagnet 42 b and the base unit 21 is arranged. However, such a design of the back gauge 15 is not shown separately.

FIG. 9 shows a schematic illustration of a further exemplary embodiment of the back gauge 15, with the same reference numerals or component designations being used again for the same parts as in the preceding FIGS. 1 to 8. In order to avoid unnecessary repetition, reference is made to the detailed description in the preceding figures 1 to 8 or reference. As can be seen from FIG. 9, it can be provided that the counter element 43 is rigidly coupled to the guide rod 46 and that the complete guide rod 46, together with the counter element 43, is received in the first bearing jaw 47 in a slightly pivotable manner. For this purpose, the bearing point between the first bearing jaw 47 and the guide rod 46 is designed in the form of a game bearing, so that a small Winkelverschwenkung or a small radial displacement between the guide rod 46 and the first bearing jaw 47 can be compensated. For centering the guide rod 46 between the counter element 43 and the first bearing jaws 47, the joint bearing 64 is formed in the form of a ball head. As a result, the contact surface 63 of the counter element 43 can be adapted to the contact surface 62 of the electromagnet 42b.

When the locking device 41 is activated, the counter element 43 is held on the electromagnet 42 b and the first bearing jaw 47 is displaced together with the stop finger 18 relative to the guide rod 46, whereby the second spring element 51 is compressed.

For detecting the contact force 50 bearing against the abutment surface 17, it can further be provided that the force sensor 60 in the form of a tensile force measuring unit is formed between the electromagnet 42b and the base unit 21.

FIG. 10 shows a further exemplary embodiment of the rear stop unit 15, again using the same reference numerals or component designations for the same parts as in the preceding FIGS. 1 to 9. In order to avoid unnecessary repetition, reference is made to the detailed description in the preceding figures 1 to 9 or reference.

As can be seen from FIG. 10, it can further be provided that the locking device 41 is designed to lock the guide rod 46 by means of a form-locking connection. In particular, provision may be made for a notch 65 to be arranged in the guide rod 46, by means of which a shaped element 66 cooperates, the shaped element 66 being designed for insertion into the notch 65. The mold element 66 is inserted in the securing direction 67 in the notch 65, whereby the guide rod 46 is locked. The stop finger 18 is thereby positioned in its working position 28 that on the base unit 21, an end stop is formed and the stop finger 18 is pressed by means of the first spring element 34 against this end stop. Furthermore, it may be expedient if the shaped element 66 has a wedge surface 68.

This can ensure that the guide rod 46 can be locked in the working position 28 of the stop finger 18.

As schematically illustrated in FIG. 10, an adjusting device 69 is formed, by means of which the shaped element 66 can be displaced in the securing direction 67. The securing direction 67 is formed transversely to the main adjustment direction 20. The adjusting device 69 may also comprise an electromagnet 42 b, by means of which the mold element 66 can be pushed into the notch 65. In particular, it may be provided here that the mold element 66 is received on a guide rod, which is displaceably mounted in the electromagnet 42b. Furthermore, a spring element may be formed, by means of which, upon release of the electromagnet 42b, the mold element 66 can be brought out of engagement with the notch 65 again. Furthermore, it can be provided that the force sensor 60 is coupled to the holding part 42a and thereby the contact force 54 can be determined. In Fig. 11, another embodiment of the back gauge 15 is again shown wherein in turn the same reference numerals or component names are used as in the previous figures 1 to 10 for the same parts. To avoid unnecessary repetition, reference is made to the detailed description in the preceding figures 1 to 10 or reference.

As can be seen from FIG. 11, it can be provided that the holding part 42a of the fixing device 41 is designed in the form of a pneumatic cylinder which has a pressing head 70 which cooperates with a pressing projection 71 of the stop finger 18. By the pressing head 70, the stopper finger 18 can be pressed against an end stop and thereby weren biased in its working position 28. In particular, it can be provided that the force sensor 60 is designed as an end stop against which the stop finger 18 is pressed. As a result, the contact force 54 can be detected. Furthermore, a buffer element 72 may be formed, which may be arranged next to the force sensor 60 and protects the force sensor 60 from excessive impact loads. The buffer element 72 may be formed, for example, in the form of a hydraulic shock absorber.

When the pneumatic cylinder is extended and the drive head 70 is pressed against the stop finger 18, the pneumatic cylinder itself can act as a second spring element 51, since the air acting in the pneumatic cylinder is compressible. By presetting the pressure in the pneumatic cylinder, the spring force of the second spring 51 can thus be adjusted.

In order to deactivate the locking device 41, the pneumatic cylinder is moved into its retracted position and thus the stop finger 18 is released for movement in the main adjustment direction 20, wherein only the small spring force of the first spring element 34 biases the stop finger 18 into its working position 28.

The embodiments show possible embodiments, it being noted at this point that the invention is not limited to the specifically illustrated embodiments of the same, but also various combinations of the individual embodiments are possible variants with each other and this variation possibility due to

Teaching for technical action by objective invention in the skill of those working in this technical field is the expert.

The scope of protection is determined by the claims. However, the description and drawings are to be considered to interpret the claims. Individual features or combinations of features from the illustrated and described different embodiments may represent for themselves inventive solutions. The task underlying the independent inventive solutions can be taken from the description.

All statements on ranges of values in objective description are to be understood as including any and all sub-ranges thereof, eg the indication 1 to 10 is to be understood as meaning that all sub-ranges, starting from the lower limit 1 and the upper limit 10 are included, ie all portions begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, eg 1 to 1.7, or 3.2 to 8, 1, or 5.5 until 10.

For the sake of order, it should finally be pointed out that for a better understanding of the construction, elements have been shown partially unevenly and / or enlarged and / or reduced in size.

S u b e c u s e c tio n a tio n s

Workpiece processing machine 31 guide carriage

 Bending machine 32 Guide rail

 Press brake 33 Distance guide slides

Workpiece 34 first spring element

 Footprint 35 Face Stop finger

Table bar 36 face basic unit

Pressing bar 37 Guide pin

 Drive means 38 stop bar

 Hydraulic cylinder 39 implementation

Lower bending tool 40 Circlip

upper bending tool 41 locking device lower tool holder 42 a holding part

upper tool holder 42 b electromagnet

 Backgauge Positioning System 43 Counterelement

 Backgauge 44 magnet holder

 Stop position 45 Fasteners

 Stop surface 46 guide rod

 Stop finger 47 first bearing jaws

 Control device 48 second bearing jaws

 Main adjustment direction 49 Distance Bearing jaws

 Basic unit 50 End section guide rod

Coupling device 51 second spring element

Base part Basic unit 52 Stop element

 Cover part of basic unit 53 Fasteners

 Fastener cover part 54 contact force

 Fingertip 55 buffer element

 Recess 56 displacement

 Working position 57 Sensor element

 Linear guide 58 second end portion Führungs¬

Retraction position rod Rear wall stop finger force sensor

display element

Contact surface Electromagnet Contact surface Counter element Spherical bearing

score

forming element

fuse direction

wedge surface

locking device

pressure head

pressuring

buffer element

Claims

Patent claims A back stop (15) for a back stop positioning system (14) of a bending machine (2), the back stop (15) comprising a stop finger (18) on which at least one stop surface (17) is formed, a base unit (21) for coupling is formed with the Hinteranschlagpositioniersystem (14), wherein the stop finger (18) by means of a linear guide (29) is coupled to the base unit (21) and the stop finger (18) relative to the base unit (21) between a pushed forward working position (28) and a retraction position (30) is displaceable, characterized in that the stop finger (18) and the base unit (21) with a return device, in particular a first spring element (34) are coupled, by means of which the stop finger (18) in his Working position (28) is biased and that a switchable locking device (41) is formed, by means of which the stop finger (18) selectively in the working position (28) can be locked or is released into its retracted position (30) for displacement, in particular against the spring force of the first spring element (34). 2. backgauge according to claim 1, characterized in that the locking device (41) comprises a holding part (42a), in particular an electromagnet (42b), wherein by applying activation energy in the holding part (42a) of the stop finger (18) relative to the base unit (21 ) is lockable. 3. backgauge according to claim 1, characterized in that the locking device (41) has a mechanically acting locking unit. 4. backgauge according to claim 3, characterized in that the mechanically acting locking unit of the locking device (41) for producing a positive connection between the stop finger (18) and the base unit (21) is formed. 5. Backgauge according to one of the preceding claims, characterized marked, that a second spring element (51) is formed, which is coupled with the interposition of the locking device (41) with the stop finger (18) and the base unit (21), wherein when locking the locking device (41) of the stop finger (18) by means of the second spring element (51) is fixed in its working position (28). 6. backgauge according to claim 5, characterized in that the second spring element (51) has a greater spring stiffness than the first spring element (34) and / or that the second spring element (51) has a larger bias voltage than the first spring element (34 ). 7. backgauge according to one of claims 2 to 6, characterized in that the holding part (42 a) of the locking device (41) relative to the base unit (21) in Hauptverstellrichtung (20) is immovably received on this and that the locking device (41) with a the holding part (42a) cooperating counter element (43) which is arranged on a guide rod (46), wherein the guide rod (46) is mounted at least on a first bearing jaw (47), wherein the counter element (43) at an end region (50 ) of the guide rod (46) is arranged and the second spring element (51) with respect to the first bearing jaw (47) opposite to the counter element (43) on the guide rod (46) is arranged. 8. backgauge according to claim 7, characterized in that the guide rod (46) is mounted with a bearing clearance in the first bearing jaws (47), so that a slight angular rotation and / or radial displacement between the guide rod (46) and the first bearing jaws (47) is possible. 9. backgauge according to one of claims 2 to 8, characterized in that the guide rod (46) is additionally mounted on a second bearing jaws (48), wherein the first bearing jaws (47) and the second bearing jaws (48) at a distance (49 ) are arranged to each other. 10. Backgauge according to claim 8 or 9, characterized in that on the guide rod (46) a stop element (52) for the second spring element (51) is formed, wherein the second spring element (51) is designed as a compression spring and between the first Bearing jaws (47) and the stop element (52) on the guide rod (46) is received, whereby the stop element (52) by means of the second spring element (51) from the first bearing jaw (47) away and thereby the counter element (43) for the first bearing jaws (47) is biased. 11. Backgauge according to one of claims 2 to 10, characterized in that the holding part (42a) is designed as an electromagnet (42b) and the counter element (43) as with the electromagnet (42b) cooperating disc is formed which frontally on the guide rod (46) is arranged, wherein the electromagnet (42b) and the counter element (43) on contact surfaces (62, 63) abut each other. 12. backgauge according to claim 11, characterized in that the electromagnet (42b) and / or the counter-element (43) are accommodated on a hinge bearing (64), so that the contact surfaces (62, 63) are aligned parallel to each other. 13. backgauge according to claim 12, characterized in that the joint bearing (64) comprises a universal joint or a ball joint. 14. Backgauge according to one of the preceding claims, characterized in that a buffer element (55) is formed, which serves for damping of the stop finger (18) during the process in the retraction position (30). 15. Backgauge according to one of the preceding claims, characterized marked, that the linear guide (29) is designed in the form of a recirculating ball guide. 16. Backgauge according to one of the preceding claims, characterized in that the linear guide (29) comprises a guide carriage (31) which is coupled to the stop finger (18) and comprises a guide rail (32) which is coupled to the base unit (21) is. 17. Backgauge according to one of the preceding claims, characterized in that a force sensor (60) is formed, which is designed to detect the amount of an action force (54). 18. Backgauge according to one of the preceding claims, characterized in that the stop finger (18) at least one display element (61) for indicating the state of the locking device (41) is arranged. 19. Backgauge according to one of the preceding claims, characterized in that a sensor element (57) is formed, which serves for detecting a relative movement and / or relative position between the stop finger (18) and the base unit (21). 20. Backgauge according to claim 19, characterized in that the sensor element (57) is designed in the form of an inductive sensor. 21. A method for positioning a back gauge (15) according to one of the preceding claims, by means of a Hinteranschlagpositioniersystems (14) of a bending machine (2), characterized in that the method comprises the following steps: - Setting a travel mode of the back gauge (15), wherein the locking device (41) is not locked and wherein the stop finger (18) by means of a rear part device, in particular a first spring element (34) is biased into its working position (28); - Method of back gauge (15) by means of the Hinteranschlagpositioniersystem (14) in its predetermined stop position (16);  - Arresting of the stop finger (18) in its working position (28) by means of the locking device (41). 22. The method according to claim 21, characterized in that during the travel mode of the back gauge (15) by means of the sensor element (57), the relative movement and / or relative position between the stop finger (18) and the base unit (21) is monitored and upon detection of a relative movement between the stop finger (18) and the base unit (21) during the process of the back gauge (15), the movement is stopped abruptly.