Method and device for controlling a press based on wedge drive tool spring condition

Abstract

A method for monitoring and assessing correct position P.sub.i of a work slide of a wedge drive tool in a press, without a position sensor. The slide of the wedge drive tool is actuated from an end position (X.sub.E) back to the starting position (X.sub.A) of the slide by a spring. The spring is arranged in the wedge drive tool. The press is opened from a lower press position to an upper press position while a slide bed of the wedge drive tool is relieved. The position of the slide is indirectly detected in that at least the restoring force of the spring is detected and evaluated.

Claims

1. A method for monitoring and assessing a position P.sub.i of a work slide of a wedge drive tool in a press, without a position sensor, comprising the steps of: actuating a slide bed of the wedge drive tool from an end position (X.sub.E) back to a starting position (X.sub.A) of the work slide; using a gas pressure spring, arranged in the wedge drive tool, to actuate the slide bed; opening the press from a lower press position to an upper press position; indirectly detecting the position of the slide; and detecting and evaluating at least the restoring force of the spring, further comprising the following steps: a) Detecting the restoring force F.sub.m (t) of the gas pressure spring at at least one point in time t, that is either at or after the beginning of the respective opening process of the press where the slide, actuated by the gas pressure spring, moves along a path x from its end position (X.sub.E) back to its starting position (X.sub.A); b) Determining, by an electronic evaluation unit, whether the restoring force F.sub.m (t) is equal to, greater or smaller than a specified target restoring force Fs (x), that the restoring force at the location x of the slide corresponds to; and c) Determining the respective condition value Z (x, t) at the point in time t, which represents a permissible or impermissible position P.sub.i of the wedge drive tool at position x between the starting position X.sub.A and end position X.sub.E, where $Z\left(x,t\right)=\{\begin{array}{cc}{P}_i\mathrm{impermissible},& \mathrm{Fm}\left(x\right)<\mathrm{Fs}\left(x\right)\\ P_i\mathrm{permissible},& \mathrm{Fm}\left(x\right)\ge \mathrm{Fs}\left(x\right)\end{array}$ d) Generating an action that stops the press if the condition value is found to be impermissible.

2. The method according to claim 1, wherein the spring comprises a wireless data transmission device to transmit the measured restoring force F.sub.m(t) to the electronic evaluation unit.

3. The method according to claim 1, further comprising a piezo element counting the strokes of the spring, and a statement about remaining service life and/or number of remaining strokes is made based on a strike rate N and the time differential of the restoring force F.sub.m(t) of the spring as measured per each stroke.

4. The method according to claim 1, further comprising using a piezo element to detect a specific vibration pattern per stroke of the spring, and a statement about remaining service life and/or a number of remaining strokes is made, or a measure of wear is detected, based on a change in the vibration pattern.

5. A device for position monitoring, without position sensors, and assessment of the position P.sub.i of the wedge drive tool in the press when actuating the wedge drive tool from the end position (X.sub.E) back into its starting position (X.sub.A) using the gas pressure spring disposed in the wedge drive tool when opening the press from a lower press position into an upper press position, comprising a measuring unit, and evaluation unit; the measuring unit at least detecting the restoring force F.sub.m(t) of the spring at a point in time t when opening the press; and the evaluation unit configured to evaluate the measured data according to the method of claim 1.

6. The device according to claim 5, wherein a shutoff directly shuts down the press depending upon the value of the detected restoring force F.sub.m(t) of the spring.

7. The device according to claim 5, further including a wireless data transmission unit to transmit measured data, comprising the restoring force F.sub.m(t) of the spring to the evaluating unit.

8. The device according to claim 5, wherein a measuring sensor system, for measuring the restoring force of the spring, and/or a data transmission unit is/are arranged in a data locker detachably connected to the spring with a housing enclosing the data locker.

9. The device according to claim 5, further including a piezo sensor for measuring a number of strokes and/or vibration characteristics of the spring or of the wedge drive tool connected to the spring.

10. A wedge drive tool for operating a press, the wedge drive tool comprising a press-controlled slide bed for driving a slide of the wedge drive tool, the slide being movable in the working direction via inclined sliding surfaces, the slide being brought into its starting position (X.sub.A) relative to a rigidly disposed driver by a spring, a device according to claim 5 to monitor and to evaluate the position P.sub.i of the slide of the wedge drive tool, when relieved from the slide bed.

Description

DRAWINGS

(1) The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

(2) FIG. 1 is a schematic representation of a press with a wedge drive tool in the closed state of the press with the upper and lower press parts moved together.

(3) FIG. 2 is a schematic representation of a press with a wedge drive tool in the open state of the press with the upper and lower press parts moved apart.

(4) FIG. 3 is a data locker configured to detachably connect to a gas pressure spring.

DETAILED DESCRIPTION

(5) The disclosure is described in detail below with reference to FIGS. 1 to 3. The same reference symbols indicate same structural and/or functional features.

(6) FIG. 1 is a schematic representation of a press 11 with a wedge drive tool 2 and the device 1.

(7) The device 1 is configured for position monitoring, particularly without position sensors, and assessment of the correct position P.sub.i of a wedge drive tool 2 between a position X.sub.E (see FIG. 1) and a position X.sub.A (see FIG. 2). The tool is disposed in a press 11.

(8) The wedge drive tool 2 is installed in a press 11. The wedge drive tool 2 has a press-controlled slide bed SB for driving a slide S of the wedge drive tool 2. The slide 9 can be moved in the working direction via inclined sliding surfaces. It can be brought into its starting position X.sub.A relative to a rigidly disposed driver T by means of a spring 10 when relived from the slide bed SB.

(9) The device 1 is configured to assess the correct functioning of the restoring spring 10 when the wedge drive tool 2 is actuated from an end position X.sub.E back into its starting position X.sub.A via the gas pressure spring 10 when opening the press 11. Measuring unit and evaluating unit are provided. Various processor known in the art may be used. At least the restoring force F.sub.m(t) of the spring 10 is detected at a point in time t when opening the press 11. The evaluating unit 31 is configured to evaluate the respective measured data.

(10) A shutoff 40 is shown purely schematically. The shutoff 40 is connected to the evaluating unit 30 to directly shut down the press 11 depending upon the value of the detected restoring force F.sub.m(t) of the spring 10.

(11) As is further visible in FIG. 1, the data transmission device 12 is configured as a wireless data transmission device to transmit measured data. Particularly, the restoring force F.sub.m(t) of the gas pressure spring 10 is transmitted in this manner to the evaluating unit 30.

(12) The data locker 14 shown in FIG. 3 has an integrated energy storage unit 17, a measuring sensor system 13 for measuring the restoring force of the spring 10, and the data transmission unit 12. The data locker 14 is provided with a housing 15 enclosing the data locker 14. A screw engagement 16 detachably connects to the spring 10. In this way, the data locker 14 can have a mobile and autonomous design and be customized depending on the type of gas pressure spring. In an optional embodiment, the data locker 14 may include target value memory units to capture target values for sensors, battery voltage, voltage monitoring of the energy storage unit 17, and the like.

(13) Furthermore, FIG. 1 shows a merely exemplary piezo sensor 50 to measure the number of strokes and/or vibration characteristics SK of the spring 10.

(14) The implementation of the disclosure is not limited to the preferred embodiments described above. Instead, a number of variants is conceivable where the solution described is used even for completely different designs.

(15) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.