EP2985094A1 - Setting tool and method for producing a permanent connection with the aid of a connecting element - Google Patents

Abstract

It is a setting device (1) and a method for producing a non-detachable connection by means of a connecting element, wherein the setting device (1) comprises a housing, a pulling mechanism (2-4) in the housing, an electric motor (7), with the the pulling mechanism (2-4) is displaceable in a pulling direction (8) from a starting position, a control device (10) for activating the motor (7) and an operating device (12) which is connected to the control device (10) , You want to be able to make the energy consumption in a setting process low. For this purpose, it is provided that the control device (10) has a force-measuring device and stops the drive of the pulling mechanism (2-4) in the pulling direction when a signal generated by means of the force measuring device coincides with a desired value (FS).

Description

The invention relates to a setting device for producing a non-detachable connection by means of a connecting element, wherein the setting device a housing, a pulling mechanism in the housing, an electric motor with which the pulling mechanism from a start position in a pulling direction is displaced, a control device for driving the Motors and an operating device which is connected to the control device comprises.

Furthermore, the connection relates to a method for producing a non-detachable connection by means of a connecting element, wherein upon actuation of an operating device, an electric motor controlled by a control device moves a pulling mechanism from a starting position to a pulling direction and thereby the connecting element or an additional element engaged therewith deformed.

The invention will be described below with reference to a setting tool with which a blind rivet nut is set. However, the invention is also applicable to other fasteners, such as a lock bolt, a blind rivet without mandrel break or a so-called "Bulb-tite-rivet" or Presslaschenniet.

To set a blind rivet nut, a mandrel is screwed into the blind rivet nut. The blind rivet nut is then inserted into a hole in a joint material until its setting head rests against the joint material. The mandrel is pulled by the pulling mechanism of the setting device in a pulling direction. In this case, the shaft of the blind rivet nut deforms on the side of the joining material facing away from the setting head and forms a closing head. When the closing head is finished, the mandrel can be unscrewed from the thread of the blind rivet nut and the setting process is completed. The movement of the pulling mechanism is usually triggered by the operator operating the operating device, for example by a pressure switch. The control device sets the motor into operation on the actuating signal generated by the operating device.

The setting process can be ended, for example, by the operator releasing the operating device. In this case, a reliable statement about the quality of the connection but virtually impossible to do.

It is therefore known to measure the distance traveled by the pulling mechanism from the starting position in the housing. When a predetermined distance has been traveled, it is believed that the closing head has been formed as desired.

The connectors used to make the non-detachable connection are mass products. Despite a high quality in the production of such mass products, a certain scatter can not avoid. The monitoring of the setting process by means of the path traveled by the pulling mechanism can therefore lead to the draw mechanism having to apply a relatively large force towards the end of the setting process. This means a considerable energy consumption, which is particularly disadvantageous in setting tools that are fed by a battery or a rechargeable battery.

The invention has for its object to make the energy consumption during setting process low.

This object is achieved with a setting tool of the type mentioned above in that the control device has a force measuring device and stops the drive of the pulling mechanism in the pulling direction when a signal generated by means of the force measuring device coincides with a desired value.

With such a setting device, it is no longer necessary to monitor the path traveled by the pulling mechanism. Rather, it is believed that one can also control the formation of the closing head or the complete completion of a forming process in other types of connectors by monitoring whether the setting process has been completed with a certain tensile force. When the predetermined force has been reached, then the closing head is formed and the movement of the pulling mechanism can be stopped. Since a maximum force is defined by the setpoint at the same time, unwanted force peaks can not occur. In an electric motor, the power consumption increases disproportionately with respect to the force, so that thereby a considerable energy saving can be achieved. The force measuring device can determine the force directly or a force corresponding or related to the force magnitude. However, it is enough to monitor the force. It is not necessary in the control of the Engage electric motor to regulate the force during movement of the pulling mechanism or to descend a certain curve. It is assumed that the setting process has been carried out with the desired quality when the setpoint of the force has been reached.

Preferably, when the signal matches the setpoint, the controller reverses the motor and moves the pulling mechanism counter to the pulling direction. This moves the pulling mechanism back towards the starting position so that virtually no time is lost for this movement.

Preferably, the control means moves the pulling mechanism to the start position. Thus, at the end of the setting process, the pulling mechanism is back where it can begin a new setting process. Since the movement into the starting position takes place immediately after the end of the setting process, basically the shortest possible cycle time is achieved for the setting process.

In this case, it is preferable for the control device to rotationally drive the pulling mechanism or a part thereof during the movement into the starting position. To set a blind rivet usually the mandrel is screwed into the blind rivet nut. After forming the closing head, the mandrel should be unscrewed from the blind rivet nut again. This can already take place during the return movement of the pulling mechanism into the starting position.

Preferably, the force measuring device has a current monitoring device, which continuously determines a current supplied to the motor, and determines from the current one of the force generated by the pulling device corresponding size. When the pulling mechanism is moved in the pulling direction, it increases to move the pulling mechanism necessary force and thus the torque required to generate the force of the engine. This is due to the fact that formed by the movement of the pulling mechanism, the closing head of the rivet sleeve of the blind rivet nut or is deformed in a locking ring bolt of the locking ring. There is a clear relationship between the torque and the current absorbed by the motor, which can be defined for example via a characteristic curve. The characteristic curve can be specified by the manufacturer of the motor or determined with simple tests. So you can also determine the achievement of the predetermined force simply by the fact that you can reach the stream continuously with a predetermined setpoint.

The control device preferably has a setpoint input. This makes it possible to change the setpoint. For example, different types of fasteners require different forces to effect deformation sufficiently. The different setpoints can be supplied via the setpoint input. The setpoint values can also be changed via an adjusting device on the setting device, for example a setting wheel or switches that can be actuated individually or in combination. Of course, it is also possible to supply the setpoints in other ways, for example via a computer interface.

The object is achieved in a method of the type mentioned above in that the control device continuously determines the force applied by the pulling force and compares it with a desired value and ends the drive of the pulling mechanism in the pulling direction when the setpoint value is reached. The force can be determined directly or indirectly over a size corresponding to the force.

As explained above in connection with the setting tool, the determination of the force is sufficient to ensure the quality of the formation of the closing head or other deformation. Since a maximum value of the force has been defined at the same time, force peaks which exceed this maximum value can not occur. Thus, corresponding current maxima are avoided, so that the energy consumption during the setting process can be made low.

Preferably, when the setpoint is reached, the direction of movement of the pulling mechanism is changed. This also keeps the cycle times short. The pulling mechanism is then quickly available for a new setting process after completion of a setting process.

This is especially true when moving the pulling mechanism to the starting position. This basically achieves the shortest possible cycle time for a setting process.

Preferably, during the return movement of the pulling mechanism in the direction of the starting position, the pulling mechanism or parts thereof are rotationally driven. This can be during the return movement of the mandrel herausdrillen from the set blind rivet nut. This also saves time.

Preferably, to determine the force to monitor the current consumption of the motor and compares it with a setpoint. The force applied by the pulling mechanism, which is necessary for the formation of the setting head or for the deformation of a locking ring bolt or other connecting element, requires a certain torque of the electric motor. The torque generated by the engine and the power consumed by the motor are clearly related. It is therefore possible to compare the recorded current with a desired value. When the current reaches the setpoint, the desired force has been reached. This is a reliable criterion for ending the setting process.

Preferably, the desired value can be changed by an input element on the setting tool. This input element may be, for example, one or more switches or a dial.

Preferably, the desired value can be changed from the outside. Thus, different setpoints can be specified, so that you can take into account different fasteners.

In an alternative embodiment, the desired value is determined during the movement of the pulling mechanism by determining an intermediate maximum of the force and multiplying the intermediate maximum by a factor (1 + x), where x ≥ 0.3. When inserting a blind rivet nut, the force that the pulling mechanism must apply first increases until the rivet sleeve buckles slightly. The force required to deform the rivet sleeve after buckling of the rivet sleeve is slightly less than the force required to buckle the rivet sleeve, so that there is an intermediate maximum here. It is now possible to set the desired value by setting it, for example, to the force of this intermediate maximum plus 30% or more. This also makes it possible to obtain a reliable monitoring of the setting process.

Fig. 1

eine stark schematisierte Ansicht von wesentlichen Funktionselementen eines Blindnietmuttersetzgeräts und

Fig. 2

einen stark schematisierten Verlauf der Kraft über den Weg beim Setzen einer Blindnietmutter.

The invention will be described below with reference to a preferred embodiment in conjunction with the drawings. Herein show:

Fig. 1

a highly schematic view of essential functional elements of a Blindnietmuttersetzgeräts and

Fig. 2

a highly schematic course of the force over the way when putting a blind rivet nut.

The following explanation is based on the example of a Blindnietmuttersetzgeräts. Corresponding functions can also be used in setting devices for other connectors, such as lockbolts or press rivet rivets.

The mechanical structure of a blind rivet nut setting device is known, for example, from a setting device with the designation "Fire Bird" from GESIPA Blindniettechnik GmbH, Mörfelden-Walldorf, Germany. For this reason, only the functional elements that are essential for understanding the present invention will be explained below.

A Blindnietmuttersetzgerät 1 has a housing not shown in detail, in which a pulling mechanism is arranged. The pulling mechanism has a receptacle 2 for a threaded mandrel 3, which can be screwed into a blind rivet nut, not shown, to set the blind rivet nut. The receptacle 3 is connected to a threaded spindle 4, which is in engagement with a transmission device 5. The transmission device 5 is connected via a transmission element 6 with a reversible electric motor 7.

The receptacle 2 can be moved in a pulling direction 8, which are symbolized by an arrow. The movement of the receptacle 2 begins in a front end position in the housing, which is also referred to simply as "start position". The receptacle 2 is also rotationally driven, as symbolized by a double arrow 9. By the rotational movement of the receptacle 2 and the threaded mandrel 3 is set in rotation, so that he in The blind rivet nut can be screwed in and unscrewed from the blind rivet nut.

The motor 7 is connected to a control device 10. The control device 10 receives electrical energy from a battery 11, which can also be expanded as a rechargeable battery or accumulator. The control device 10 is connected to an operating device 12, which has an operating element in the form of a pushbutton or pressure switch 14.

The control device 10 supplies energy to the electric motor 7 via a supply line 14 in the form of electrical current. In the supply line 14 (or at another position in the control device 10), a current sensor 15 is arranged, which continuously determines the current through the supply line 14.

The control device 10 has a comparison device 16, which continuously compares the current determined by the current sensor 15 with a setpoint input FS fed via a setpoint input 17.

Fig. 2 shows in schematic form the course of the force F of the pulling mechanism over the path s, which covers the receptacle 2 in a setting operation of a blind rivet nut. Shown is a function 18. From the function 18 it follows that the force F initially increases when a blind rivet nut is set. In many cases, an intermediate maximum 19 results when the rivet sleeve of the blind rivet nut begins to deform. Thereafter, the force initially drops slightly and then increases again, which is due to the fact that the closing head of the rivet sleeve forms. The setting process is terminated when the force F reaches the setpoint FS.

The force whose course through the function 18 in Fig. 2 is shown is generated via the transmission device 5 by a torque of the motor 7. The current consumption of the motor 7 correlates sufficiently with the torque, ie when the torque increases, then the current consumption of the motor increases. This can be represented for example by a characteristic which can be provided by the manufacturer of the engine or determined by simple tests.

It is now assumed that it is sufficient for forming the closing head to apply the blind rivet nut with a maximum force. This is represented by the setpoint FS. It is not necessary to let a force beyond the threaded mandrel 3 and the receptacle 2 act on the blind rivet nut. An additional force would result in an increased power consumption, because the current consumption usually increases not linear, but approximately square with the torque. Accordingly, upon reaching the setpoint FS, the control device 10 can immediately end the setting process, without the need for further signals, for example the signal of a displacement sensor.

It is also not necessary to include the continuously determined force in a control process. Rather, the motor 7 can be relatively easily controlled during the entire setting process. Basically, it is only necessary to provide the motor 7 with electrical energy so that it rotates to move the receptacle 2. It is only necessary that the motor reaches the force corresponding to the setpoint FS.

The force required for the proper formation of the closing head of the blind rivet nut can be specified by the manufacturer of the blind rivet nut and printed, for example, on the packaging of the blind rivet nut. This force can be input via the setpoint input 17 in the setting device 1. The conversion between force and current can then take place automatically in the control device 10.

The setpoint input 17 can be supplied in different ways. In a very simple way, the setpoint FS is specified by the manufacturer of the setting device 1 and stored, for example, in a non-volatile memory. In this case, the setpoint FS is changeable only by a maintenance specialist, but not by the user. Alternatively, the setpoint FS can also be changed by the user. For this purpose, for example, a setting wheel or an adjustment switch device may be provided on the setting device 1. In general, it is sufficient if the dial has a sequence of digits 1 .... x, which can be matched with a mark. Finally, the setting tool can also have a computer interface, via which one can then enter a desired value.

The setpoint FS can also be set in other ways. As explained above, the force curve shows an intermediate maximum 19. This intermediate maximum 19 allows in any case, in sufficient approximation, a statement about the deformation behavior of the rivet sleeve of the blind rivet nut. It is then possible to set the desired value FS such that it is, for example, 30% greater than the intermediate maximum 19. In this case too, the setting process can be completed with sufficient reliability.

The control device 10 controls at the moment in which the force (or according to the power absorbed by the motor 7) matches the target value, the motor 7 and moves the pulling mechanism with the receptacle 2, the threaded mandrel 3 and the threaded spindle 4 against the pulling direction 8. This movement can take place up to the starting position, so that the setting device 1 passes through a complete cycle, in which an operator by pressing the button 13, however, only has to specify the start. The rest of the setting process is automatic.

During the return movement, the control device 10 can also rotationally drive the receptacle 2 in order to drill the threaded mandrel 3 out of the blind rivet nut. This also keeps the cycle times short.

The current sensor 15 can also be arranged elsewhere. It can, as explained above, also be part of the control device 10. It can also be arranged between the control device 10 and the battery 11.

Claims (14)

Setting device (1) for making a non-detachable connection by means of a connecting element, wherein the setting device (1) has a housing, a pulling mechanism (2-4) in the housing, an electric motor (7) with which the pulling mechanism (2-4) a control device (10) for driving the motor (7) and an operating device (12) which is connected to the control device (10), characterized in that the control device (10) has a force measuring device and the drive of the pulling mechanism (2-4) terminated in the pulling direction when a signal generated by means of the force measuring device coincides with a desired value (FS). Setting device according to claim 1, characterized in that the control device (10) in accordance with the signal with the Setpoint (FS) reverses the motor (7) and moves the pulling mechanism (2-4) against the pulling direction (8). Setting tool according to claim 2, characterized in that the control device moves the pulling mechanism into the starting position. Setting tool according to claim 3, characterized in that the control device (10) rotationally drives the pulling mechanism (2-4) or a part thereof in the movement into the starting position. Setting tool according to one of claims 1 to 4, characterized in that the force-measuring device comprises a current monitoring device (15) which continuously determines a current supplied to the motor (7), and from the current one of the force generated by the pulling mechanism (2-4) corresponding size determined. Setting tool according to one of claims 1 to 5, characterized in that the control device (10) has a setpoint input (17). Method for producing a non-detachable connection with the aid of a connecting element, in which, on actuation of an operating device (12), an electric motor (7) controlled by a control device (10) moves a pulling mechanism (2-4) from a starting position to a pulling direction (8) moves and thereby deforms the connecting element or an additional element engaged therewith, characterized in that the control device (10) that by the pulling device (2-4) Applied force continuously determined and compared with a setpoint (FS) and ends the drive of the pulling mechanism (2-4) in the pulling direction when the setpoint value. A method according to claim 7, characterized in that on reaching the desired value (FS), the direction of movement of the pulling mechanism (2-4) changes. Method according to claim 8, characterized in that the pulling mechanism (2-4) is moved into the starting position. Method according to one of claims 7 to 9, characterized in that in the return movement of the pulling mechanism (2-4) in the direction of the starting position the traction mechanism (2-4) or parts thereof rotationally drives. Method according to one of claims 7 to 10, characterized in that one monitors the current consumption of the motor (7) and determined from the recorded current one of the traction device (2-4) recorded force corresponding size. Method according to one of claims 7 to 11, characterized in that the desired value (FS) is variable by an input element on the setting tool. Method according to one of claims 7 to 11, characterized in that the desired value can be changed from the outside. Method according to one of claims 7 to 11, characterized in that one determines the desired value (FS) during the movement of the pulling mechanism (2-4) by determining an intermediate maximum (19) of the force and the intermediate maximum with a factor (1 + x), where x ≥ 0.3.

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