ELECTRONIC ANGLE MEASURING DEVICE FOR A BENDING MACHINE FOR MEASURING THE BENDING ANGLE BETWEEN THE LIMBS OF A SHEET

Abstract

An electronic angle measuring device for a bending machine for measuring the bending angle between the legs (4) of a sheet (5) using a sensor element (7) is described, which supplies angle-equivalent signals in a contactless manner to a signal processing unit (9), which has a microprocessor and a memory unit and is connected to a digital display (10). To provide simple measuring conditions, it is proposed that the sensor element (7), the signal processing unit (9), and the display (10) form an angle measuring device (6) which is fastenable on the upper tool (1) of the bending machine and is usable as a handheld encoder, and which has a motion sensor (11), which is connected to the signal processing unit (9) and detects the lowering and/or raising movement of the upper tool (1), for triggering the measuring procedure

Claims

1. An electronic angle measuring device for a bending machine for measuring bending angle between legs of a sheet said device comprising: a sensor element that supplies angle-equivalent signals in a contactless manner to a signal processing unit, which has a microprocessor and a memory unit and is connected to a digital display, wherein the sensor element, the signal processing unit, and the display form said angle measuring device, which is fastenable on an upper tool of the bending machine and is configured to be used as a handheld encoder, and which has a motion sensor that is connected to the signal processing unit and detects a lowering and/or raising movement of the upper tool, so as to trigger a measuring procedure.

2. The electronic angle measuring device according to claim 1, wherein the motion sensor is configured as a multi-axis accelerometer.

3. The electronic angle measuring device according to claim 2, wherein the signal processing unit corrects a signal of the accelerometer by a signal component based on the acceleration of gravity.

4. The electronic angle measuring device according to claim 1, wherein the device has a housing that has at least one permanent magnet in rear wall thereof adapted to fasten on the upper tool.

5. The electronic angle measuring device according to claim 1, wherein the signal processing unit has a radio interface.

6. The electronic angle measuring device according to claim 1, wherein the signal processing unit signals overshooting or undershooting of programmable tolerance limits of an angle to be measured.

7. The electronic angle measuring device according to claim 1, wherein the signal processing unit analyzes measured values, which are stored in the memory unit during the lowering and raising movement of the upper tool, according to mathematical methods to increase accuracy of the measured values.

8. The electronic angle measuring device according to claim 1, wherein the sensor element has a rotating mirror deflecting a laser beam onto the two legs of the sheet and forms a measured value from the reflected beam received in an emission direction.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0018] The subject matter of the invention is illustrated by way of example in the drawings. In the figures

[0019] FIG. 1 shows a bending machine having a digital angle measuring device according to the invention in a partially cutaway, schematic side view

[0020] FIG. 2 shows this bending machine in a schematic vertical section, and

[0021] FIG. 3 shows the electronic angle measuring device according to the invention in a simplified block diagram.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] The illustrated bending machine has an upper tool 1, which can be lowered and raised, and which interacts with a lower tool 2 in the form of a matrix and is assembled from stamp segments 3 arranged next to one another. A digital angle measuring device 6, which comprises a sensor element 7 having a mirror, which is rotated about a rotational axis parallel to the vertex axis of the bending angle between the two legs 4 of the sheet and deflects a laser beam in a plane perpendicular to the vertex axis onto the two legs 4, is fastened onto the upper tool 1 for measuring the bending angle between the legs 4 of a sheet 5 to be bent. The laser beam passes in this case through a measuring gap 8 between two stamp segments 3. Since the sensor element 7 has a receiver for the laser beam reflected in the emission direction on the legs 4 and the intensity of the reflected laser beam is greatest when the laser beam is perpendicular to the legs 4, the rotational position of the mirror can be specified for the laser beams which are perpendicular to the legs 4 of the sheet 5, as indicated in FIG. 2. Therefore, the respective bending angle between the two legs 4 may be derived from these rotational positions of the mirror.

[0023] For this purpose, according to FIG. 3, the sensor element 7 is connected to a signal processing unit 9, which analyzes the measurement signals received from the sensor element 7 and outputs the measured bending angle at a display 10. This display 10 is required not only for the use of the angle measuring device as a handheld device, but rather also enables the bending angle and other displayed data to be read off during use as a machine encoder, without having to turn away the view decisively from the sheet 5, which is anyway located in the field of vision.

[0024] Since the angle measuring device 6 has a motion sensor 11 connected to the signal processing unit 9, the angle measurement can be synchronized with the motion of the upper tool 1 via the detection of the motion of the upper tool 1, without having to make use of the machine controller. The electronic angle measuring device 6 can therefore be used without complex refitting work in existing bending machines if a measuring access of the sensor element 7 to the two legs 4 of the sheet 5 is possible, which can be ensured in a simple manner in the case of the typical assembly of the upper tool 1 from stamp segments 3. The angle measuring device 6 is solely to be fastened accordingly on the upper tool 1. For this purpose, providing at least one permanent magnet 12 in the region of the housing rear wall of the angle measuring device 6 suggests itself.

[0025] If the motion sensor 11 is designed as a multi-axis accelerometer, by means of its signals for the acceleration of gravity, the angle measuring device 6 can be aligned in a simple manner in relation to the horizontal vertex axis of the bending angle between the two legs 4, which is predefined by the matrix and the stamp segments 3. In addition, it is possible to analyze a measurement signal corrected with respect to the acceleration of gravity, so that exclusively accelerations of the angle measuring device 6 can be used for ascertaining the motion of the upper tool 1.

[0026] Storing measured values during the raising movement of the upper tool 1 is particularly advantageous for the formation of accurate measurement results. By way of measurements also during the rebound of the sheet 5 after the bending procedure, reverberation procedures can be eliminated by the signal processing unit 9 with the aid of suitable mathematical methods and the final result can be improved. The measuring procedure is preferably ended by a microprocessor, which computes an end of the bending procedure on the basis of an analysis of the measured value family. Alternatively, ending the measuring procedure after passage of a fixed time span or after traveling a certain distance of the upper tool ascertained from the signal of the motion sensor is also possible.

[0027] If the angle measuring device 6 has a radio interface 13, data can thus not only be transmitted wirelessly from the angle measuring device 6 outward, but rather also data can be transmitted from the outside to the angle measuring device 6. To be able to set different operating modes for the angle measuring device 6, the angle measuring device can additionally be provided with an input 14. To be freed of cable terminals, the angle measuring device 6 is preferably to be equipped with batteries or rechargeable batteries 15 for the power supply.