EP1992429A1 - Setting tool with means for monitoring setting procedures - Google Patents

Abstract

The tool (1) has a head piece (2) for reception of a rivet (20), a device for gripping a riveting bolt and a pulling device coupled to the latter, with measurement of variables, e.g. the tensile stress or position, for the pulling device, for control of the rivet joint by comparison of measured values with stored reference values. Also included are Independent claims for the following: (a) a placing control method for a rivet placing tool; (b) a head piece for a rivet placing tool; (c) a rivet control method for a rivet placing tool; (d) a rivet with controlled placing.

Description

description

The invention relates to a setting tool with means for controlling setting operations.

Setting tools with means for controlling the setting process are known.
So will in DE 44 01 134 a method is described in which a force component is measured over the path of the stroke and compared with a setpoint curve. This is to check whether the setting process has taken place properly.
EP 0 738 551 ( US 5,666,710 ) discloses a device for checking the setting of blind rivets. Here, the traction and the position of the Zugschaftes are measured. An integrator determines the converted energy and compares it with a setpoint.

A disadvantage of these known means for controlling the setting process is that although it can be determined with a certain probability whether the setting process is within a given tolerance limit, the cause of an error can not be determined. A placement process can result in a whole series of errors. For example, errors of the operator, such as by incorrect application of the setting device, too wide holes, false rivets, errors in the rivet itself. Blind rivets also always run the risk that the rivet only covers the part to be fastened, but not the counterpart.

The object of the invention is to provide a setting tool that monitors the setting process and also detects the cause of an error occurring. Moreover, it is an object of the invention to provide a comprehensive control over various parameters of a setting process.

This object is achieved in a surprisingly simple way already with a setting tool according to the features of claim 1.
Thereafter, a setting tool is provided with a head piece, in particular for receiving the rivet, a device for gripping and / or pulling and a pulling device connected to the device for gripping and / or pulling, which means for measuring the occurring during the setting process size values, means for Comparison of the measured values with stored values and a device for determining a cause, in particular a cause of error, for the deviation of measured from stored values.
The setting tool, which can be of various types, such as riveting tools, Blindnietmuttersetzwerkzeuge,
Lock ring pin set tools, has sensors.
By means of the sensors, various parameters such as position of the pulling device, time since the beginning of the setting process or the applied tensile stress can be measured. These measured values are compared with stored values. The stored values not only contain a setpoint curve, which, if not followed, assumes a faulty setting process, but also values for specific errors. These values can be used as mere individual values but also as a setpoint curve with various parameters that describe a specific error. available. The amount of stored error causes includes at least one cause of error, which may already be sufficient for some applications. Preferably, however, a plurality of different causes of errors are stored. In addition to errors, however, the cause of deviations, which are still within the tolerance range, but are not ideal, can be determined. In this case, the setting tool on a specific setting process, which is defined for example by the rivet used, the material used and its thickness, preprogrammed. A programming on several different setting processes is conceivable.
The invention makes it possible to eliminate the cause of the error as quickly as possible. Since operating errors are also detected with the invention, the setting device is also outstandingly suitable for untrained operators. By the invention, the quality of each setting process can be controlled. This is for example of great advantage in aviation technology. Although partially rivets are used there, which has been subjected to an X-ray inspection. Whether the riveting process then went without errors, can not be guaranteed by the control. With the invention, it would theoretically even be possible to dispense with the complex X-ray inspection, and still be able to guarantee the durability of the riveted joint.

Preferred embodiments and further developments of the invention are to be taken from the respective subclaims.

In a preferred embodiment of the invention, the measured size values comprise the tensile stress exerted by the traction device and / or the position of the traction device and / or the time since the beginning of the respective setting process and / or the angle to the surface on which the Setting device is set to. By means of these values a comprehensive error diagnosis is possible. This can also be done by converting the values in curves or multi-dimensional maps.

In a preferred embodiment of the invention, it is checked whether the device is attached at the correct angle. Often, operators do not set the jig exactly at right angles. This leads to a reduction in the strength of the connection.
It is also useful to check if a wrong rivet has been used. There are also rivets that are not visually different, but made of other materials and thus have a completely different strength. This can be done for example by the course of the tension exerted by the pulling device.
Another embodiment controls whether the rivet is defective. For example, material defects in the rivet lead to a different force curve.
Another embodiment controls whether the bore intended for the rivet is too wide or too narrow.
Also, whether a rivet is in the device can be easily determined with the setting tool according to the invention, for example by measuring the applied tensile stress. It is particularly useful to check whether the rivet covers both parts to be joined. Especially with blind rivets, it often happens that the rivet does not cover both parts to be joined. The operator can not control this himself, because he sees only the part to be fixed, but not the other side. If the rivet only detects the part to be set, the tension exerted by the pulling device increases later, or with a larger stroke. So the mistake can be easily determined.
In a further embodiment of the invention, it is monitored whether the setting tool has a defect. So For example, the oil level of the tractor may be too low. As a result, the pulling device is stiff and no longer works with the intended traction. Ideally, several of these causes of error are programmed into one device. The programming of the device can be done by performing a test series in which deliberate mistakes are made. The deviations of the measured values which occur during the respective errors can then be stored in the device in order to be compared with later measured values. It is also conceivable, not only to perform a pure error control, but also to compare the deviation of a still lying in the respective tolerance area setting process with an ideal value.

A preferred embodiment of the invention has a device for measuring the position of the traction device and / or for measuring the tension exerted by the traction device. The position of the pulling device and the applied tension are two of the most important parameters that can be used to determine a number of causes of failure.

As provided in an expedient embodiment of the invention, the tensile stress exerted by the pulling device is measured with a stretch measuring strip. Such a strain gauge for measuring voltages is reliable and cheap. The tensile stress is substantially proportional to the tensile force exerted by the traction device.

In an alternative embodiment, the device for measuring the tensile stress exerted by the traction device comprises a piezoelectric sensor.

This piezoelectric sensor requires no power supply.

An expedient embodiment of the invention has a capacitive sensor for measuring the position of the pulling device. Such a capacitive sensor is much more accurate than commonly used optical sensors.

In one development of the invention, the angle to the surface on which the setting tool is attached, measured by means of at least three sensors arranged on the head. These sensors touch the surface on which the device is attached when it is set at right angles. Thus, a frequent error of the operator can be diagnosed.

In a development of the invention, the setting tool has means for data storage and / or further processing. Thus, the measured values can be statistically evaluated. For example, the user can control exactly how many setting operations were made, how many were faulty, and what causes for mistakes. In addition, it is conceivable to evaluate the values of the correctly executed setting processes, for example in the form that deviations of the values from the ideal values are stored and evaluated. So a comprehensive quality control is possible.
On the part of the manufacturer of the tool, the function of his devices can be monitored. It is also conceivable that the tool is not paid for itself, but that the manufacturer provides the tool to the customer and that this then pays, for example, according to the number of settling operations carried out. Also, to grant a manufacturer's warranty, it is extremely advantageous if the manufacturer can recognize potential errors by the tool itself and exclude them if necessary.

In an expedient embodiment of the invention, the means for data storage and further processing can be reset, in particular for a service of the device. For example, after resetting, the device may be delivered to the customer like a new device.

An expedient embodiment of the invention has a chip for comparing measured and stored values and / or for data storage and further processing. Such a chip can be tailored exactly to the requirements of the device. Furthermore, the smallest possible size is possible. Compared to usable EPROMs, the chip also has the advantage that it can be manipulated much more difficult.

In an expedient embodiment of the invention, the comparison of measured and stored values and / or data storage and processing in the device takes place. Using modern microelectronics, it is possible to integrate the entire evaluation in a handy device.

Expediently, an independent energy source in the device, in particular a rechargeable battery, is provided for the means for comparing measured and stored values and / or for data storage and further processing. This ensures that stored measured values are not lost even in the event of a prolonged power failure.

The setting tool expediently has a counter, the rivet setting cycles and / or errors and / or error causes counts. Thus, a statistical error evaluation is already possible with the device itself.

In a further development of the invention, the setting device has a device for date and / or time recording. Thus, the setting processes and possible errors can be assigned to a certain point in time. It is so comprehensible in retrospect, when and therefore often where exactly a specific error has happened.

A development of the invention has a device for transmitting measured values to an external unit. As an external unit, for example, a computer system is conceivable, via which a further storage and evaluation of the measured values supplied by the setting device can be made. The individual setting devices could, for example, be assigned to the system via their device numbers.

Expediently, the device for transmitting measured values comprises a device for transmitting infrared, ultrasound or radio signals, in particular "bluetooth". For example, bluetooth technology provides a cheap and reliable standard wireless component.

Alternatively, the external unit may include a mobile terminal. Thus, a wireless transmission over long distances is possible, such as the manufacturer of the setting device.

In an expedient embodiment of the invention, the setting tool has a device for switching off the Nietsetzgerätes and / or indication of the cause of the fault, in response to a faulty Nietsetzvorgangs generated signal, on. So it is also possible, for example, not to perform a setting process, if an error is displayed from the beginning. If the device is not set at right angles, it will not trigger at all. Also if there is no rivet in the device. Even if only the component to be fastened is detected when setting a blind rivet, it is still possible to cancel the setting process while indicating the cause of the error.

It is also conceivable to generate the signal by an external unit, for example a connected computer.

In a further development of the invention, the setting tool can also include a device for connection to a local network, whereby a fast transmission and further processing of the data is possible. As part of successive assembly steps, for example, on the assembly line, a quick message of an error is particularly advantageous so that not the entire assembly process comes to a halt for a long time.

The traction device of the setting device can be operated electrically, in particular with a rechargeable battery, electrohydraulically, hydraulically or hydropneumatically. It is also possible to provide a completely wireless device with battery and wireless data transmission.

In a further development of the invention of a non-wireless device, the setting device has a line for supplying compressed air or electricity and at least one further line for transmitting the measured values, and the further line forms a line with a connection with the one line. So no two lines must be connected for power supply and data exchange. It is conceivable, a combination plug with for example a compressed air line and adjacent lines for data transmission to provide.

In a further development of the invention, the setting tool performs a test cycle after switching on. Thus, errors that affect the device, even before use are excluded. For example, to check whether the tool is mechanically correct, the pulling device can automatically be moved back and forth after switching on. If the traction device is stiff, the tool indicates the error.

The object of the invention is further achieved by a method for controlling setting operations, in particular rivet setting operations, according to the features of claim 28.
Thereafter, a part to be placed in a setting tool, preferably a setting tool according to the preceding claims is inserted, then a tensile force is exerted on the part to be set by a pulling device.
The values occurring during the setting process are measured. The values measured in this way are compared with stored values. Finally, based on this comparison, the cause for deviating measured values from a set of stored causes is determined.

Furthermore, the invention according to the features of claim 38 relates to a head piece for a setting tool with means for measuring the size values occurring during the setting process, with a device for comparing the measured values with stored values and with a device for determining the cause of the deviation of the measured from stored value from a set of stored causes.

This headpiece fulfills the object of the invention as well as the setting tool. By a head piece, it is possible to equip an existing setting tool with the functions of the invention.

The invention further relates to a setting tool with a piezoelectric sensor and a method for setting parts to be set, preferably rivets, in particular a device and a method for setting rivets with tension measurement, and a head piece for a setting tool.

Rivet connections are used in industrial manufacturing in a variety of ways for the assembly of components. Particularly in the automotive and aerospace industries, high demands are placed on the stability and long-term load capacity of subassemblies under the safety aspect. The stability of a rivet connection depends decisively on the course of the riveting process. If, for example, the pin of a blind rivet breaks too early, the strength and durability of the riveted connection is endangered or at least not optimal. The same applies, for example, if the blind rivet was not just inserted into the opening in the sheets or the opening for the rivet is not optimally adapted. The latter occurs, for example, by non-circular openings or those with incorrect diameters.

Known riveting tools use rivets with preset parameters, such as the tensile force to be applied. at
In optimal conditions, a riveting operation using such a device may also achieve an optimal result, but deviations will occur not recognized by the target parameters, which affect the strength of the connection. This is particularly significant, as a poor riveted joint may well give the appearance of a correctly placed blind rivet or a rivet nut during external inspection. Such faulty connections have negative effects on the quality of the assemblies produced therewith and can even have fatal consequences in safety-sensitive areas, such as aircraft construction.

Out EP 0 454 890 a rivet setting device is known, which is provided with a force measuring device, which ensures that the rivet setting device operates with a predetermined tensile force. The force measuring device has a strain gauge.
A disadvantage of such a strain gauge that for this purpose a power supply is necessary, and that the strain gauge does not convert the tensile force of itself in a voltage signal.

The object of the present invention is therefore to provide an improved control of rivet joints during riveting. This object is already achieved in a surprisingly simple manner by a setting tool according to claim 60, and a method for setting according to claim 77 and a head piece for a setting tool according to claim 82. Advantageous developments are given in the respective dependent claims.

Accordingly, a rivet processing tool, in particular rivet setting tool with a head piece for receiving in particular a rivet, a device for gripping and / or pulling in particular a rivet pin and a the device for gripping and or pulling particular rivet pin connected pulling device provided, which additionally comprises a device comprising at least one piezoelectric sensor for measuring the tension of the pulling device.

The device for measuring the tension of the pulling device can be used to determine and evaluate their measured values. It has been shown that a measurement of the tensile stress curve during a riveting cycle reproduces detailed information about the rivet setting process and, in particular, faulty rivet setting processes can be determined on the basis of the tensile stress profile.

The piezoelectric sensor used for measuring the tensile stress is inexpensive, provides accurate readings and can be accommodated in a small space. In addition, such a sensor provides a voltage signal. Thus, in contrast to conventionally used Dehn-measuring strip (DMS), a voltage supply is not required.

The invention is suitable for all types of rivet processing and setting tools, such as rivet setting tools, Blindnietmuttersetzwerkzeuge, Schließringbolzenetzetzwerkzeuge etc.

Additional parameters can be recorded to control the setting process. Advantageously, for example, the instantaneous position of the traction device can be determined via a device for measuring the position of the traction device, such as a displacement sensor, so that it is possible to evaluate tension-displacement-value pairs.

In a simple way, the tensile stress can be measured indirectly by means of a pressure sensor, which measures, for example, the counterforce exerted via the pulling device on a part of the riveting tool.

In particular, for industrial applications hydraulically operated traction devices are advantageous with which fast setting cycles can be performed with reproducible setting parameters. However, the invention also includes electrical, electro-hydraulic and hydropneumatic traction devices. Among the electric traction devices, a wireless device with integrated battery is particularly advantageous.

For the detection and evaluation of the device for measuring the tension of the pulling device, a corresponding device can be accommodated in the setting device in an advantageous manner. Furthermore, a counter can be accommodated in the setting device that counts setting cycles. For example, maintenance intervals can be monitored with a counter that records the number of set cycles based on the measured tension values. In addition, the counter can be used to check, in particular for large assemblies with a large number of rivets, if any rivets have been omitted.

The device for evaluation and detection may also include a date and / or time acquisition device. For example, warranty periods and maintenance periods can be checked by a date entry. The device can thus be set up, for example, to start the date acquisition after a certain number of rivet setting cycles, so that, for example, trial cycles can be carried out before the start of date recording.

With an additional recording of the time can be traced, for example, when faulty rivets were set.

The tension measured values and / or the counter readings can also be transmitted via an appropriate device for transmitting tension measured values to an external unit. This unit can be, for example, a computer for data evaluation and / or control. Advantageously, the signal transmission can be accomplished with a device for transmitting infrared, ultrasound or radio signals.

Furthermore, the data can also be transmitted via a mobile network to a mobile terminal. Thus, for example, for remote diagnostics in case of faulty functioning of the device, the data can be transmitted directly to a maintenance department or the manufacturer. This also allows the manufacturer to check whether the required maintenance intervals have been complied with.

Preferably, the means for gripping a rivet pin further comprises jaws which are operated via a chuck connected to a pulling spindle. The tension is transmitted via a tension spindle.

The setting device can also be provided with a device for connection to a local network for rapid distribution of the data to a plurality of external evaluation units.

It is also within the scope of the invention to specify a corresponding method for checking setting processes, which can be carried out in particular with a setting device according to the invention. The procedure intends to Inserting part into an opening provided for this purpose and then to set the part to be set to exert a tensile force on the part to be set, preferably the rivet pin by means of a pulling device, wherein at least one measured value is obtained during application of the tensile force, by the voltage applied to the rivet pin Traction is caused or influenced. The measured value can be obtained at a predetermined time or stroke of the pulling device and can thus provide information about any not optimally placed rivets.

Preferably, several measured values are obtained at regular time intervals during the application of the tensile force. Thus, a temporal course of the applied tensile force can be determined and thus obtain detailed information about the riveted joints.

Particularly advantageous is the use of measured data obtained with a piezoelectric pressure sensor. In the case of large tensile forces, even an extremely small sensor delivers sufficiently high voltages for precise and interference-free measurements.

Finally, the invention relates to a head piece for a setting tool, which comprises a device comprising at least one piezoelectric sensor for measuring the tension exerted by the pulling device.
This head corresponds in its function to the solution of the object according to the invention according to claim 60, with the difference that here the device required for measuring the tension is completely integrated with a piezoelectric sensor in the head piece. It is thus possible to provide a head piece with the function according to the invention for an existing setting tool. That has that Advantage that no complete setting tool must be purchased. The header can be provided with corresponding connections for setting tools from different manufacturers. The advantage of the head piece according to the invention is that the piezo sensor does not require a power supply.

Finally, the invention relates to a rivet. The setting device according to the invention according to the features of claim 1 is dependent on a comparison of measured values, such as the tensile stress at a certain time of the setting process of a uniformity of the setting operations. Disadvantages are mainly rivets that have different properties. If the properties are very different, for example due to different materials or due to manufacturing tolerances, the device can not be optimally programmed. Then, the tolerance limit for a setting process must be increased, which in turn is disadvantageous for an optimal setting result. The object of the invention was therefore also to provide a rivet, which has substantially constant properties.

This object is achieved in a surprisingly simple manner by a method for controlling a rivet according to claim 97. Thereafter, it is provided that at the rivet, in particular with a setting tool according to claim 1 to 60, a tensile stress is applied, the change in length of the rivet is measured and compared with a desired value. The measurement is made in order not to damage the rivet, in the elastic range. Based on a setpoint of the change in length or a path-force curve can be tested whether the rivet has the intended properties.

In a preferred embodiment of the invention, the tension is applied to the rivet pin of a blind rivet.

In a further development of the invention rivets that are not within a predetermined tolerance range, sorted out. The sorting can be done automatically by the control device.

In a further development of the invention, rivets which lie within a predetermined tolerance range are permanently marked. Thus, the performed quality inspection is visible on the rivet. Confusion with unexamined rivets are excluded in this way.

The invention will be explained below with reference to preferred embodiments and with reference to the accompanying drawings, wherein in the individual drawings, like reference numerals refer to the same or similar components.

Fig. 1

eine schematische Ansicht einer ersten Ausführungsform der Erfindung,

Fig. 2

Graphen der Zugspannung als Funktion der Zeit,

Fig. 3A bis 3D

verschiedene Ausführungsformen externer Einrichtungen zur Erfassung und Auswertung von Zugspannungs-Messwerten,

Fig. 4

eine schematische Querschnittsansicht durch eine Ausführungsform der Erfindung,

Fig. 5

eine schematische Ansicht eines Kopfstückes eines Setzgerätes mit Sensoren, und

Fig. 6

Graphen der Zugspannung verschiedener Setzlinge als Funktion der Zeit.

Show it:

Fig. 1

a schematic view of a first embodiment of the invention,

Fig. 2

Graphs of tensile stress as a function of time,

Fig. 3A to 3D

various embodiments of external devices for recording and evaluating tension measured values,

Fig. 4

a schematic cross-sectional view through an embodiment of the invention,

Fig. 5

a schematic view of a head piece of a setting tool with sensors, and

Fig. 6

Graphs of the tension of different seedlings as a function of time.

In the following description, reference will be made primarily to the riveting operation, which means setting a rivet. In this case, however, the described rivet setting includes the setting of blind rivets, rivet nuts and in particular the setting of locking ring bolts, even if this is not explicitly mentioned. Insofar as a different headpiece, mouthpiece, lining or other receptacle is required for the particular embodiment, a person skilled in the art can make appropriate adjustments to the current requirements.

In Fig. 1 is a schematic view of a first embodiment of the rivet setting device according to the invention shown. The Nietsetzgerät 1 comprises a head piece 2 with adjusting nut 22 for receiving a rivet 20, a body portion 6, and a handle 16. With a manually operable trigger 18, a pulling device inside the Nietsetzgerätes is triggered, which means for gripping the shaft or Nietstifts the rivet 20 is connected, so that the pin is pulled into the device. In this case, the device for gripping the shank or rivet pin preferably comprises a chuck with two or more clamping jaws. The traction device is supported on the head part 2 of the rivet setting device, so that the tension exerted on the rivet pin is translated into a pressure exerted between the head part and the traction device. At the head part 2 there is a sensor unit 3, preferably with a piezoelectric sensor, which measures the pressure arising between the head part 2 and the pulling device when pulling the rivet pin. The sensor generates a tension signal substantially proportional to the tension. This voltage is transmitted via a cable 8 to an external device 12 for the detection and evaluation of Zugspannungs measured values either directly or from the sensor unit initially amplified, in which case the amplified signal is transmitted.

In addition, a separate evaluation electronics 15 can be accommodated on a part 14 fastened to the handle, which comprises, for example, an electronic counter with date and / or time function.

The transmission to an external evaluation unit can alternatively take place via cable connections via corresponding devices for the transmission and reception of infrared, ultrasonic or radio signals. In particular, the Nietsetzgerät can also be set up to transmit the signals via a mobile network to a terminal, which can reach large distances between riveting and external evaluation.

In this embodiment, the rivet setting device 1 also has a displacement sensor 4, which determines the instantaneous position of the traction device via a device for measuring the position of the traction device and transmits a corresponding signal to the external device 12 via a cable connection 10. The displacement sensor may be, for example, an optical-electronic or an inductive displacement sensor.

Eig. Figure 2 shows graphs of tensile stress as a function of time over rivet setting cycles. Graph 100 shows the typical course of the tensile stress under optimal conditions. has a minimum of tensile stress. Up to this minimum, the rivet head is compressed by the pulling force exerted by the pulling device of the rivet setting device. Thereafter, the traction continues to grow until the rivet pin leaves and the tension abruptly drops to zero.

Graphs 101, 102, and 103 show traces of tensile stress at non-optimal conditions. Graph 101 shows the course of the tensile stress at a too large hole diameter. In this case, the minimum between the two maxima is not as deep as in the optimal case and at a later time. In addition, a higher tension must be applied in the case of a too large hole diameter until the pin is torn off and the tearing off takes place at a later time.

Graph 102 shows the profile of the tensile stress at a rivet and graph 103 not fully inserted into the hole in a riveting operation without material, i. H. without the rivet was inserted into a hole in a sheet. In both cases, the minimum of the tension, as well as the time of the tearing of the pin at a later time compared to the curve under optimal conditions.

It is clear from these graphs that the time course of the tensile stress can provide detailed information about the condition of the set rivet.

The following refers to the FIGS. 3A to 3D which show embodiments of external means for detecting and evaluating tension measurements of the invention.

In Fig. 3A schematically an evaluation unit 24 is shown, which is connected via a cable connection 8 with the sensor unit 3 of the rivet setting device 1. Instead of the cable connection 8, the sensor unit and the Evaluation unit are also connected to each other via a transmitting / receiving device for infrared, ultrasound or radio signals, wherein the sensor is equipped according to a transmitter and / or receiver.

The evaluation unit 24 comprises an LCD display 26 and controls 28. On the LCD display current results of measurements are shown, such as the maximum tensile stress reached. The measurement and evaluation results are determined by a suitable measuring electronics in the unit 24. The controls can be used to enter various functions, such as making a reference measurement, warning thresholds, or resetting current readings.

Fig. 3B shows an extension of this system, wherein the evaluation unit 24, a printer 32 is connected via a cable connection 30. Via the printer 32 current measurement results and other data can be output. The printer can be controlled, for example via the controls 28.

In Fig. 3C an embodiment is shown in which via a cable connection 8, the measured values of the sensor unit 3 of the rivet setting device are transmitted to a computer 34 as an evaluation unit. For this purpose, the computer, preferably a workstation can be provided with a suitable plug-in card, in which a transmitter is housed for the transmitted Spannungsmeßwerte. For example, the voltage measurements are digitized by means of an ADC module at regular intervals and can then be further processed with suitable software. The processed measurement data and evaluation results are then displayed on the screen 36 of the computer.

Fig. 3D shows a further embodiment in which a plurality of rivet setting devices is connected via cable connections 81, 82, 83 and 84 to an evaluation unit 38. The embodiment is in Fig. 4 shown as an example for four riveting tools. However, this structure can be extended to any number of devices. The structure may also be applied to a single riveting tool as well. Each rivet setting device is connected via the cable connections to one of the blocks 381 to 384 of the evaluation unit 38.

The evaluation unit 38 is in turn connected via a connection 40 to a network node 42, from which the data can be distributed to a plurality of computers 341 to 344.

Fig. 4 shows a schematic cross-sectional view through an embodiment of the invention, based on the principle of the tensile stress measurement can be explained. In the body part 6 is a hydraulic cylinder 50. Running in the cylinder 60 is a hydraulic piston 52 to which is attached a pulling spindle 54 which transmits the force exerted by the piston to a chuck 56 fixed thereto. If a force is exerted by the piston in the direction of the arrow by a suitable hydraulic fluid is pressed into the cylinder portion 51, so jaws 58 are first compressed by the retracting lining 56 until a rivet pin located therebetween is gripped and clamped. The jaws then pull the rivet pin further into the head part 2 of the rivet setting device until it breaks off from the rivet head approaching the adjusting nut 22. The piston can also be operated hydropneumatically, wherein a further, pneumatically operated piston, for example, in the in Fig. 1 shown, on the handle attached portion 14 may be housed, the hydraulic fluid is pressed into the hydraulic cylinder 50.

By the pulling force exerted on the lining 56 a pressure on the head part 2 is exerted. The head part 2 is attached to the body part 6, that the pressure is not transmitted directly to the sleeve of the head part 2, but via a located between the head and torso part piezoelectric material part 31. A resulting piezo voltage can then be transferred by means of the electrical connections 60 and 62 to a suitable connector 64. Likewise, the pressure sensor may also be connected to a suitable measuring and evaluation electronics, which is integrated in the riveting tool itself.

Fig. 5 shows a schematic plan view of a head piece for a setting tool according to the invention. Evident is the adjusting nut 22 of the head piece 2. To the adjusting nut 22 around three sensors 70 are attached. When the unit is attached, all three sensors only touch the part to be fixed when the unit is at right angles to the part to be fastened. So it is possible to check if the operator makes a mistake. If the device is not set at a right angle, an electronic system ensures that the device is blocked so that the setting process can not be started at all.

Fig. 6 Figure 4 shows four graphs in which, in a set operation, the applied tension is plotted against time, with the x-axis indicating the time and the y-axis the force. Graph 90 shows the force-time curve when setting a rivet nut. Here, the force first increases strongly in the elastic range, changes into the plastic range and remains in the area until the end of the setting process about constant. Graphs 91, 92 and 93 show the force-time profile for various blind rivets. Here, the force also increases in the area of plastic deformation, until the rivet pin tears off and the force drops to zero. It can be seen that the force-time curves are very different for different rivets. Therefore, it is necessary to program the device for certain setting operations. Due to deviations from these curves, a number of causes of error can already be detected. If, for example, the force in the elastic area of a blind rivet increases later, the blind rivet has only grasped the part to be set. If the hole is too wide, the curve increases more flat in the plastic area. In this way, a whole series of errors can be detected by comparison with stored error causes. It is also conceivable to measure a force-displacement curve or both a force-time and a force-displacement curve. By evaluating set operations, ideal values and typical deviations for specific causes of error can be determined exactly.
The evaluation can be done by setting various desired fields 94, 95, 96. If the curve on the right past the field 94, then the blind rivet detects only the part to be fastened, the transition from the elastic to the plastic area is not exactly in the field 95, the borehole is too far or does not drop the tensile stress in the field 96 to zero a wrong rivet was used. A precise error analysis is carried out by many such fields, which are run through during the setting process and make a cause of error recognizable. By juxtaposing individual fields, certain error causes are also excluded if the target values are adhered to. If, for example, field 94 is complied with, it is impossible that the counterpart is not included. So a clear assignment of the different causes of error is possible.

Claims (15)

Setting tool with a head piece, in particular for receiving a rivet, a device for gripping and / or pulling and a traction device connected to the device for gripping and / or pulling,
characterized by : - means for measuring the size values occurring during the setting process; - means for comparing the measured values with stored values; a means for determining a cause, in particular a cause of error, for the deviation of measured values of stored values from a set of stored causes. Setting tool according to claim 1, characterized in that the size values comprise the tension exerted by the pulling device and / or the position of the pulling device and / or the time since the beginning of the respective setting operation and / or the angle to the surface on which the setting device is attached , Setting tool according to claim 1 or 2, characterized by the stored error causes: - The device is not set at the correct angle; and or - wrong rivet used; and or - rivet damaged; and or - drilling intended for the rivet too wide or too narrow; and or - no rivet in the setting tool; and or - Rivet does not capture both parts to be joined; and or - Setting tool has a defect. Setting tool according to one of the preceding claims, characterized in that the angle can be measured by means of at least three sensors arranged on the device head. Setting tool according to one of the preceding claims, characterized in that comparison of measured and stored values and / or data storage and further processing takes place in the device. Method for controlling setting processes, in particular rivet setting processes,
comprising the steps: - Inserting a part to be placed in a setting device, preferably a setting device according to the preceding claims; - Applying a tensile force on the part to be set by a pulling device;
characterized by the steps - measurement of the occurring size values; - Comparison of the measured values with stored values; - Determining a cause, in particular a cause of error, for the deviation of measured stored values from a set of stored causes. A method according to claim 6, characterized in that the size value of the tension exerted by the tension device and / or the position of the pulling device and / or the time since the beginning of the respective setting process and / or the angle to the surface on which the setting tool is attached, is measured Head piece for a setting tool, in particular for a setting tool according to claims 1-7, characterized by : - means for measuring the size values occurring during the setting process; - means for comparing the measured values with stored values; a means for determining a cause, in particular a cause of error, for the deviation of measured values of stored values from a set of stored causes. Setting tool, in particular rivet setting tool, comprising a head piece, in particular for receiving a rivet, - A device for gripping and / or pulling, in particular a Nietstiftes and a traction device connected to the device for gripping and / or pulling, in particular a rivet pin,
marked by - A device comprising at least one piezoelectric sensor for measuring the tension exerted by the traction device. Setting tool according to claim 9, characterized
by a device for measuring the position of the pulling device. Method for controlling setting processes, in particular rivet setting processes,
comprising the steps of - Inserting the part to be set, in particular a rivet, in an opening and the - Applying a tensile force on the part to be placed, in particular the rivet pin
by a pulling device, characterized in that
at least one measured value is obtained during the application of the tensile force, which is caused or influenced by the tensile force applied to the part to be set, in particular on the rivet pin. Headpiece for a setting tool, in particular for a setting tool according to claim 9-10,
marked by
a device comprising at least one piezoelectric sensor for measuring the tension exerted by the pulling device. Method for controlling a rivet, in particular for a setting tool according to claim 1 to 3, characterized in that on the rivet, a tensile stress is applied, the change in length of the rivet is measured and compared with a desired value. A method according to claim 13, characterized in that rivets, which are within a predetermined tolerance range, are permanently marked . Rivet controlled by a method according to any one of claims 13 to 14.

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