EP3181260B1 - Slip detection - Google Patents

Description

The invention relates to a hand-Blindnietsetzgerät and a method for its operation.

State of the art

From the prior art, such as the WO 03/059551 A , which forms the basis for the Oberbergriff of claims 1 and 11, the DE 10 2013 221 789 A1 , of the WO 2009/074312 A1 , of the EP 1 382 406 A2 , of the US 5,661,887 A. , Blindnietsetzgeräte are known. To make the connection, a blind rivet is used together with the setting tool.

Blind riveting is a mechanical joining process in which a blind rivet is inserted into a prefabricated hole on two components to be joined together and plastically deformed with the blind riveting tool. The deformation of the blind rivet is carried out by a rivet mandrel, which is pulled by the Blindnietsetzgerät. Once the deformation is completed, the rivet mandrel breaks at a predetermined breaking point. In this way, a frictional connection of both components. The blind rivet therefore comprises two parts, a rivet sleeve and a rivet mandrel.

Industrial Blindnietsetzgeräteanordnungen are usually realized by means of the following means: superordinate control (eg base station, rivet controller) for one or more rivet setting devices, a power unit depending on the requirement for the power output of Nietsetzgeräte, one or more rivet setting devices. The Nietsetzgeräte usually include at least one pulling device for pulling the mandrel, which by means of a drive (pneumatic, hydraulic, electric) can be driven. The rivet mandrel is held by means of clamping jaws during the setting process. During setting, the jaws can slip more or less strongly on the rivet mandrel. With greater wear of the jaws and more contamination of the riveting equipment reduces the frictional contact and increases the slip between jaws and rivet mandrel. This can even result in too much contamination of the rivet mandrel not enough of the jaws be held and thus the rivet mandrel can not be demolished by the rivet.

It is desirable to detect such weary equipment conditions in good time, in order to prevent poor quality riveted joints. It would also be preferable if the riveting tool could operate autonomously, that is without the need for a higher-level control.

Disclosure of the invention

According to the invention, an electric hand rivet setting device and a method for operating such a hand riveting setting device are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

The manual rivet setting device is a device with a housing which comprises the claimed features. The device is intended as a self-measuring and process-monitoring device with fully integrated device control. This means that the device automatically monitors the setting process carried out by the device and preferably also assesses it qualitatively, without the need of a higher-level instance.

The device is realized in such a way that, as a compact and self-contained device, it is easy to hold in the hand and thus can be easily transported and guided. Preferably, a battery operation is provided, which makes the device independent of an external power supply. The housing preferably also comprises a means for the automatic removal of a torn off rivet mandrel after the setting process, so that regardless of the current position of the device, the torn rivet mandrel can be safely removed by means of a channel-like Nietdornabführung to a rivet mandrel container also disposed on the device. Preferably, the Nietdornabführung is realized by means of an air flow.

The rivet setting device according to the invention is adapted to the force data recorded by means of the device-internal electronics and sensors with respect to the pulling force exerted on the rivet mandrel during a setting operation and the path data detected by the device-internal electronics and sensor system with respect to the path traveled by the rivet mandrel during a setting process log and store it internally, so that for each set by the device setting process, a force-way record is provided by the device, which it allows a graph to be displayed with regard to the force-displacement curve, in particular also after the setting process, but also during the setting process. The abscissa of a coordinate system for displaying the graph preferably corresponds to the path, and the original coordinate of the coordinate system preferably corresponds to the force. It would also be conceivable alternatively to ablate the force on the abscissa and the path on the ordinate of the coordinate system. The data are stored internally as force-tow data pairs in a device memory and linked with the associated setting process.

The rivet setting device comprises comparison means, preferably computer-implemented on the device control, on which a software is executable, which is able to perform the comparison. The comparison means is provided for comparing at least two existing force-path profiles, which can be assigned to different setting processes, with one another, and deriving from the comparison result an action specific to the riveting apparatus.

Advantages of the invention

By a suitable evaluation of the force-displacement curves, a required replacement or a required cleaning of the riveting tool can be detected and displayed by the riveting tool automatically and in good time.

The data pairs automatically assigned to each other by the device, consisting of force data and travel data, which are acquired by the sensors during a setting process and represent the graph of a setting process, form a curve, which is also referred to as a riveting curve. This allows a software-based wear monitoring by means of the analysis of the curve as well as a monitoring for contamination of the housing components of the Neitsetzgerätes included device components, in particular the mechanism for gripping and / or pulling the rivet mandrel. In particular, the gripping mechanism is usually subjected to high contamination, for example by metal abrasion from the rivet mandrel during setting operations.

By means of such proactive self-monitoring carried out automatically by the device, a reduction of the cleaning and maintenance intervals with high process reliability of the riveting can be ensured.

A first force-path curve is maintained in a first device mode as a reference curve for comparison with all other force-path curves. This reference history is preferably from a reference rivet setting process provided shortly after a new, overhauled, or recently refurbished or cleaned grooving machine was put into service. The reference profile creates an assessment criterion for the state of the device-internal components for all subsequent setting processes. During the second setting process, that is to say a setting process following the reference rivet setting process, the second force-path curve is detected and provided in the device memory, preferably including linking to the corresponding setting process. In subsequent subsequent setting operations, this is repeated for each of these setting operations, that is also detected during the setting process force-path curve detected by the sensor and stored in the device memory and preferably linked, so that a variety of force-displacement paths comparable to the reference curve and stored in the device memory for comparison purposes with the reference curve. The storage in the device memory is preferably realized by means of a database, but can also be realized proprietary. The further the detected force-path curves deviate from the reference curve in the context of the comparison, the more the state of the device-internal components has changed since the reference rivet setting process. This may be an indication of pending maintenance or cleaning of the components that a device user should be aware of.

A plurality of force-path curves are maintained in a second alternative or additionally provided device mode for comparison with each other. In contrast to the reference Nietsetzvorgang hierbai successively be compared with each setting process provided force-path profiles compare with each other, that is, the currently provided force-path curve is compared in each case with the previous force-path curve, and so on. The overall results of all previous comparisons are considered indicative of any upcoming maintenance or cleaning of the components. The riveting operation preceding the current riveting operation therefore represents a temporary reference course, which, however, after completion and comparison with the current rivet setting process, is again replaced by the latter. For the upcoming one Nietsetzvorgang then acts again the currently completed Nietsetzvorgang as a temporary reference curve and so on. In retrospect, therefore, a number of X force-displacement curves, so-called riveting curves, are considered one after the other and with a recognizable successive extension or successive force increase during the associated Nietsetzvorganges the action is derived and thus made a tendency deterioration of the device state visible to the operator. In particular, it is also computer-implemented to examine a multiplicity of consecutive, preferably device-internal, stored force-path curves corresponding to the temporal sequences of their provision with respect to a displacement of the graph defined by the force-displacement data, especially by comparison of the graphs with one another Direction and / or direction.

A preferably provided and tolerance-dependent triggering of the action makes it possible to hide changes in the force-path course, which are not indicative of internal changes in the components or are tolerable, when the action is triggered. By a particularly preferred sectional possibility of assigning tolerance ranges, it is possible to selectively hide and show very specific sections of the force-path course when the action is triggered.

In a preferred operating mode of the device, it is provided, in particular, to analyze the graph of a force-path curve with respect to its geometric properties, preferably device-internally by means of the device control included in the device, in particular with respect to the steepness of a preferably selectable graph section or for detection sawtooth-like gradients on the graph. On the graph itself, a curve discussion or other mathematical analysis is more preferably performed, which allow retrospective conclusions about the setting process, which is the basis of the graph.

According to the invention, a slip between the clamping jaws of the rivet setting device and the rivet mandrel during a pulling operation is provided by means of the comparison, as long as the clamping jaws hold the rivet mandrel. The path length which has occurred during a setting operation until the rivet mandrel has been torn off and the pulling force applied thereby allows conclusions to be drawn about the slip between the clamping jaws and the rivet mandrel. ever longer, for example, the way, the greater the slip. This may indicate soiled jaws in which the corrugation is contaminated by material deposits for gripping the rivet mandrel and thus has become less grip.

As a preferred action, a user instruction is provided, in particular with regard to a displacement of the force-path profiles with one another in the direction of force and / or in the direction of travel, wherein it is provided in particular to visualize the user information on a display means, which is preferably encompassed by Nietsetzgerät. The worker thus receives a maintenance signal early on and can replace the device at the next shift change or give it for inspection. The worker himself can take immediate action, depending on the urgency of the current state of the device.

By means of a network connection encompassed by the rivet setting device, the action is preferably forwarded to a remote instance, for example to a central maintenance server or to a similar device. The action is preferably wireless, for example, forwarded by means of WLAN or Bluetooth. Such instances can then take immediate action. For example, it is preferably provided that the rivet setting device or individual device functions can be controlled as a function of the comparison result, for example, can be unlocked or blocked for further operation. This would be realized by means of network connection, for example, also from a distance.

It is particularly expedient if the pulling device can be regulated as a function of the result of the comparison, so that the tensile force, preferably depending on the slip, can be changed. These measures allow the rivet setting even with already critical to be considered wear conditions or contamination conditions continue to operate without loss of quality in terms of riveting, because these states are now easily ausregelbar and a worker, for example, a still ongoing work without interruption so easily finish.

The aforementioned advantages also apply to the computer-implemented method according to the invention. It is understood that the features mentioned above and those yet to be explained not only in the combination specified in each case, but also in other combinations or alone, without departing from the scope of the present invention.

The invention is illustrated schematically by means of embodiments in the drawings and will be described in detail with reference to the drawings. In the figures, identical or functionally identical features are provided with the same reference numerals, unless stated otherwise.

figure description

FIG. 1

shows roughly schematically a device according to the invention;

FIG. 2

shows roughly schematically a riveting curve;

FIG. 3

shows roughly schematically the rivet curve in sections;

FIG. 4

shows steps of the method according to the invention.

Detailed description of the drawings

This in FIG. 1 shown riveting tool is used for setting consisting of a rivet and a rivet mandrel rivets or blind nuts. It is a Ackugerät for manual operation. Stationary devices would also be conceivable. Provided is a device head 10 with mouthpiece for holding the rivet mandrel. Along a common axis of the device head 10 and / or a force sensor with Nietdorndurchführung 9 and / or a trapezoidal or ball screw 7 with Nietdorndurchführung and / or preferably a Nietdornbehälter 12 are arranged adjacent to each other. A pinch mandrel clamped during operation by the jaws of the mouthpiece can be removed after its demolition by the aforementioned components 10, 9, 7 by means of a Nietdornabführungskanals (not shown) to the Nietdornbehälter 12 by suitable movements of the riveting tool or a breeze.

The trapezoidal or ball screw 7 is driven by means of an electric motor 5, preferably in conjunction with a transmission 6. On the trapezoidal or ball screw 7, a travel sensor 8 is arranged, which detects the traversed by the trapezoidal or ball screw 7 path directly or indirectly, by means of traversed by the trapezoidal or ball screw 7 angle of rotation. Alternatively, the travel sensor 8 could also be arranged on the motor 5 and detect its rotational angle.

Reference numeral 11 denotes a device-internal device control 11 with communication module and display (not shown), which may be at least partially included by the housing of the riveting tool. The rivet mandrel container 12 may also be at least partially enclosed by the same housing.

The entire arrangement mentioned above is supplied with electricity here by means of a rechargeable battery 1, for this purpose a wiring harness 3 is provided, which extends inside the housing. For switching on and off the riveting the starter switch 4. Reference 2 indicates the interface with power electronics for driving the motor. 5

At least the components 2, 3, 5, 6, 7, 8, 9 are completely enclosed in this preferred embodiment by the housing of the riveting tool, preferably also the device control 11. The device control 11 is capable without any higher-level control of completely self-sufficient rivet setting processes to control or regulate and to log or analyze. The device controller 11 is so connected to the sensors 8, 9, so that they can store the continuously supplied by the sensors during a setting process amount of data. For this purpose, the force-path data is stored in a device-internal force-path data memory 13. This power-path data memory 13 may be included in the device controller 11. Power-path data comparison means 14 may also be included in the device controller 11. The device controller 11 is preferably a microprocessor, in particular with a real-time operating system, wherein the device functions, including the comparison processes and the riveting curve analyzes, are preferably implemented by means of a computer-implemented program stored in the device memory and executable on the microprocessor or the operating system. By means of this program, the inventive method is implemented as claimed, preferably by means of individually executable program threads.

A quality analysis of the riveted joints can also be made using reference datasets and / or force-displacement datasets. In addition to a pure OK / NOK information (OK = no error, NOK = error) to the user, force-displacement curves or analysis results related thereto can be displayed visually in the display of the preferably device controller 111. The Nietsetzgerät invention is set up so that it riveting can also transmit to a higher-level institution. Such would be used for visualization purposes of a monitor. The preferred solution presented here makes it possible to retrospectively evaluate the force-displacement diagrams of each individual rivet connection, which was realized within a production line. It is also possible to assign riveting curves to individual components internally, for which purpose the rivet setting device according to the invention has been provided for connection to complex component databases. Such databases may preferably also be stored in the device memory.

In order to perform a rivet slip detection, the invention provides different strategies, which can preferably also be linked to one another by a device user:
In a first variant, the reference curve must be determined by means of a reference rivet setting process and can preferably be provided with a tolerance. The reference curve can also be read or entered manually on the device and a tolerance can also be entered. Optionally, the individual points of the reference curve can be edited, for example by means of a device comprising keyboard and display. A second variant makes it possible to work without a reference curve by comparing the rivet curves with each other to determine tendencies, that is, changes in the path and / or the force.

In a variant according to the invention, it is also possible to specify a maximum tolerance band for the amplitude of permissible irregularities in the course of the riveting curve, for the detection of a sawtooth profile or of discontinuous discontinuous progressions, which may also indicate mechanical errors. The rivet setting device according to the invention is provided to automatically detect a saw tooth course within a riveting curve. The amplitude of the sawtooth on the rivet curve indicates slipping of the rivet mandrel between the jaws, ie slipping is detected over a permissible, in particular a maximum vertical spread of the rivet and lead to a maintenance note as action. Due to a preferably predefinable maximum allowable tolerance curve or tolerance section for the rivet in the direction or in the direction of force, a limit curve for the way or the force is specified. If this limit curve is exceeded, the riveting result may still be OK, but the riveting tool preferably gives one Maintenance note. Each individual rivet curve point can preferably be provided with individual deviation tolerances.

FIG. 2 roughly schematically shows a rivet curve 28 (force-displacement curve) in general, which is provided by the Blindnietsetzgerät during a Blindnietsetzvorgangs. In particular, it can be seen in the graph, the beginning of the riveting process 21, followed by buckling of the rivet sleeve 22 (force peak and subsequent break-in), the pushing together of the sheets by the rivet 23 until the sheets lie on each other 24, and a force increase 25 in the rivet connection itself, which further compresses the sheets, up to the maximum force 26 and abort 27 of the rivet mandrel at its predetermined breaking point, including Sägezahnbereiche 30. On the ordinate the path is removed, which was zurückkgelegt to demolition and on the abscissa the corresponding force, which on has acted on the rivet mandrel. The data come from the device sensor 8,9.

FIG. 3 shows roughly schematically the rivet curve FIG. 2 , wherein a tolerance window is predetermined around the sawtooth region 30. The tolerance window causes a sawtooth within the tolerance window to lead to no action, only courses outside the tolerance range trigger an action. A limit curve section in the force increase region 24 is also shown. The limit curve section 29 causes a course within the limit curve section 29 to lead to no action, only courses to the right of the limit curve section 29 trigger an action.

FIG. 4 shows the essential steps of the method according to the invention, namely detecting a distance traveled S0; detecting S1 a path-dependent applied force; providing S2 of a first force-path course by pairwise assigning the values of a first force data set that can be assigned to a first setting process to the values of a first path data set that can also be assigned to the first setting process and providing S3 of a second one Force-path course by assigning the values of a second force data set, which can be assigned to a second setting process, to the values of a second path data set, which can be assigned to the second setting process; and comparing S4 of both force-path profiles with each other and deriving an action S5 from the comparison result. The method is computer-implemented by means of a program executable on the device controller 11 and preferably can be called up wirelessly by the riveting device from an internet server. Program updates are carried out automatically or at the push of a button by the rivet setting device at the request of the user. <U> REFERENCE LIST </ u> battery pack 1 Battery interface with power electronics 2 harness 3 starting switch 4 engine 5 Gearbox (with offset) 6 Trapezoidal / ball screw + mandrel guide 7 travel sensor 8th Force sensor with rivet mandrel feedthrough 9 Riveting equipment for holding the rivet mandrel 10 Control electronics / Communication / Display 11 Nietdornbehälter 12 Force-displacement data storage 13 Comparison means for force-displacement data 14 Beginning riveting process 21 Buckling of the rivet sleeve 22 Pushing the sheets together 23 Sheets lie together 24 Elastic and plastic force increase 25 maximum strength 26 Demolition of the rivet thorn 27 Force-path curve, grap, riveting curve 28 tolerance ranges 29 Jerking, sawtooth 30 steps S0 to S5

Claims (15)

1. Handheld electric rivet setting device, in particular with removable battery, for setting riveting means with a tear-off rivet pin, comprising a device head (10) with a mechanism for gripping the rivet pin, a pulling device (7) for pulling on the rivet pin and a drive (5) for driving the pulling device (7), an in particular offset gear mechanism (6) preferably being provided between drive (5) and pulling device (7), a first sensor (8) for detecting a travel covered being arranged in the device in such a way that, by means of the first sensor (8), the travel covered by the pulling device (7) can be detected, and in that a second sensor (9) for detecting an applied force being arranged in the device in such a way that, by means of the second sensor (9), the pulling force applied by the pulling device (7) can be detected, the handheld rivet setting device additionally having a device memory (13) and a comparison means (14) and being configured to provide the data detected by means of the sensors (8, 9) for a first force-travel curve (28) and a second force-travel curve (28) in the device memory (13), and to compare (14) the two curves with each other by using the comparison means (14) and to derive an action from the comparison result, the device head (10) comprising clamping jaws, which can be activated by means of the pulling device (7), for gripping the rivet pin, characterized in that the action provided is to determine slip between the clamping jaws and the rivet pin during a pulling operation, wherein the rivet setting device is provided for rivet slip detection, for automatic detection of a saw-tooth curve within a riveting curve which indicates slippage of the rivet pin between the clamping jaws, wherein slippage beyond a permissible, in particular a maximum, vertical range of scatter of the riveting curve is detected and leads to a maintenance indication as the action, and wherein a limiting curve for the travel or the force can be predefined, and wherein each individual riveting curve point can be provided with individual deviation tolerances.
2. Rivet setting device according to Claim 1, wherein the first force-travel curve (28) is reserved as a reference curve for the comparison, in order to compare further force-travel curves (28) that are provided with this reference curve.
3. Rivet setting device according to Claim 1, wherein a multiplicity of force-travel curves (28) are reserved for the comparison, in order preferably to compare successively detected force-travel curves (28) with one another, preferably in accordance with the order of the detection.
4. Rivet setting device according to one of the preceding claims, wherein provision is made, during the comparison, to take into account a tolerance range (29) which defines permissible comparison tolerances.
5. Rivet setting device according to Claim 4, wherein the tolerance range (29) can be defined section by section along the force-travel curve (28), in particular also individually for preferably all individual value pairs of force and travel, in order to provide a plurality of mutually independent tolerance curves (29) along the force-travel curve (28) .
6. Rivet setting device according to one of the preceding claims, wherein provision is made to analyse the graphs of a force-travel curve (28) with respect to its geometric properties, preferably within the device by means of a rivet device controller (11) comprised by the device, in particular with respect to the slope of a preferably selectable graph section, or in particular for detecting characteristic curves (30) for the riveting.
7. Rivet setting device according to one of the preceding claims, wherein, to detect the slip between the clamping jaws and the rivet pin during a pulling operation, the force-travel curves (28) provided one after another in the device memory are compared with one another by the comparison means in order to determine trends, i.e. changes with respect to the travel and/or the force.
8. Rivet setting device according to one of the preceding claims, wherein the action provided is a user reference, in particular with regard to a displacement of the force-travel curves among one another in the force direction and/or in the travel direction and/or with respect to a reference curve, wherein provision is made to visualise the user reference on a display means (11), which is preferably comprised by the rivet setting device itself.
9. Rivet setting device according to one of the preceding claims, wherein the action provided is to control the operation of the rivet setting device or individual rivet setting device functions, depending on the comparison result, for example to initiate enablement or blockage.
10. Rivet setting device according to one of the preceding claims, wherein the action provided is to control the operation of the pulling device (7), depending on the comparison result, for example to change, preferably to raise and/or lower, the pulling force as a function of slip.
11. Computer-implemented method for operating a handheld rivet setting device for setting riveting means, which comprise a tear-off rivet pin, preferably a rivet setting device according to one of the preceding claims, comprising the steps: detecting (S0) travel covered by a rivet pin pulling device during a rivet setting operation in the form of travel data, detecting (S1) a force applied by the rivet pin pulling device during the setting operation in the form of force data, providing (S2) the data as a force-travel curve (28) that can be assigned to the setting operation in a device memory (13) of the handheld rivet setting device, and providing (S3) a second force-travel curve (28) in the device memory (13) by detecting the values from a second force dataset, which can be assigned to a second setting operation, and detecting the values of a second travel dataset, which can likewise be assigned to the second setting operation, comparing (S4) the two force-travel curves (28) with each other by a comparison means (14) of the handheld rivet setting device, and deriving (S5) an action specific to the handheld riveting device from the comparison result, the device head (10) comprising clamping jaws, which can be activated by means of the pulling device (7), for gripping the rivet pin, characterized in that the action provided is to determine slip between the clamping jaws and the rivet pin during a pulling operation, wherein the rivet setting device for rivet slip detection automatically detects a saw-tooth curve within a riveting curve which indicates slippage of the rivet pin between the clamping jaws, wherein slippage beyond a permissible, in particular a maximum, vertical range of scatter of the riveting curve is detected and leads to a maintenance indication as the action, and wherein a limiting curve for the travel or the force can be predefined, and wherein each individual riveting curve point can be provided with individual deviation tolerances.
12. Method according to Claim 11, wherein the first force-travel curve (28) is reserved as a reference curve for comparison with a multiplicity of further force-travel curves (28) that can be provided by the rivet setting device.
13. Method according to Claim 11, wherein the first and the second force-travel curve (28) are compared with each other in accordance with the chronological order of their detection.
14. Method according to one of the preceding method claims, wherein the clamping jaws are activated by means of the pulling device (7) during the setting.
15. Method according to Claim 14, wherein the pulling device (7) is changed as a function of slip during the setting.

Images