EP0860221B1 - Pressing device - Google Patents

Description

The invention relates to a pressing device for connecting workpieces, with a press tool and a motor drive for actuating the pressing tool via a pressing path and with a control device, the drive control device.

For connecting pipes it is known to use sleeve-shaped press fittings to be used for the purpose of making a Pipe connection pushed over the pipe ends and then radially be pressed together, both the press fitting and the pipe is plastically deformed. Such pipe connections and the associated press fittings are for example from the DE-C-11 87 870, EP-B-0 361 630 and EP-A-0 582 543 are known.

The pressing is done with the help of pressing devices, like them in various embodiments, for example in the DE-C-21 3782, DE-A-34 23 283, EP-A-0 451 806, EP-B-0 361 630 and DE-U-296 04 276.5 are known. The presses have one Press tool with at least two or even more Press jaws that are used radially inwards during the pressing process Formation of a substantially closed press room moves become. The pressing tool is interchangeable on the rest Part of the press attached so that one to each Suitable press tool diameter used for the press fitting can be.

There is an electric drive for the movement of the press jaws provided that additionally with a hydraulic unit can be combined. As part of a pressing process, the Drive back a pressing path that usually started with a Empty path begins until the press jaws on the press fitting come to the plant. The deformation follows on the further pressing path of the press fitting and the pipe end up to a final press position. Here the drive is switched off automatically it in the form of a force limiting element, for example a torque clutch or a hydraulic switching valve, be it by a limit switch in connection with a Jaw closing sensor on pressing tool (DE-U-296 02 240.3), on June 19, 1997 in the industry model role and thus made accessible to the public.

The known pressing devices usually have a drive control device with which only the switching on and off of the drive can be effected, in which no power control device for the purpose of changing the performance target is available on the press path. The press tool With such presses, the full, d. H. uncontrolled power. hereby builds up significant kinetic energy, and especially in the first phase, bridging the idle stroke. This leads to high stresses on the pressing tool especially in the area of the final pressing position, because there is still Significantly converted kinetic energy into heat must become. To avoid this disadvantage is in DE-U-297 03 052.3 with reference to the unpublished German patent application 196 33 199.4 (priority document of EP-A-0 824 979, disclosed February 25, 1998) a drive control device disclosed in the case of a power control device the power of the drive via the press path in the Way is limited that the press tool towards the end of the press has less kinetic energy than without power control. This measure ensures that the maximum force, on the moving parts of the pressing device works, is significantly reduced and ideally equal to that to be applied when the workpieces are deformed Strength is.

In a simple version, the performance is two-stage in the Way controlled that in the first phase of the press path and Low performance, especially when overcoming the free travel is specified, which is then applied to the press fitting in adaptation to the resulting compression resistance is increased. By storing a variety of control parameters, a setpoint curve can be very close adapted the course of the compression resistance in the way be that the stress on the power parts of the pressing device, for example when the pressing jaws hit on the press fitting and especially at the end of the press path, be kept low (DE-U-297 03 052.3). You can also a large number of setpoint curves can be stored in order to the right one for every type and size of press tool To be able to select the setpoint curve. After DE-U-297 03 052.3 can be selected manually by an appropriate Switch or by means of one located on the press tool Coding done. It is noted that the DE-U-297 03 052.3 is the priority document of the present patent.

The performance can be achieved with the sequence control described above of the drive is already close to the course of the compression resistance adjust and thereby the stress of the Greatly reduce the tool and ultimately its service life significantly increase. Nevertheless, it is necessary to provide a setpoint curve that is ideal Provides a performance surplus to circumstances. This Excess output is then supposed to be properly pressed ensure if there are no ideal conditions, for example, when the friction between the jaws and press fitting due to the material used or are unfavorable due to rust formation if worn moving parts of the press have become stiff or if the available electrical voltage is lower than usual or voltage fluctuations occur. The surplus power is made under ideal conditions noticeable with a strain that is essential is lower than with a drive without power control, however is still unnecessarily high.

The invention has for its object a press trained in such a way that a possible extensive adaptation to the compression resistance possible is, without this justifying the danger that the Performance under unfavorable conditions is not sufficient.

This object is achieved in claim 1. The Power control device and the setpoint curve or Setpoint curves are part of a follow-up control with feedback. This is expediently done in such a way that the setpoint curve or each setpoint course of one the control bandwidth defining control corridor with upper and lower control limits is included.

The basic idea of the invention is therefore an actual value control perform and power control based on the difference between the actual value and that of the setpoint curve to one at a certain point in time. The Follow-up control allows the setpoint curve to be sent to the Compression resistance under ideal conditions - movable Parts run smoothly, favorable friction conditions on the press fitting, Mains or battery voltage at design level - to adapt, so that even with these conditions just so much pressing force is generated as necessary. Should the compression resistance will be higher or the voltage will be lower corrected this by the subsequent regulation in the sense that the Performance specification for the purpose of adaptation to the setpoint curve is increased, for example by adjusting the Phase cut in a triac or pulse width modulation with a transistor as a power control element. Also creeping changes, such as wear or pollution, are compensated for by the subsequent regulation.

Especially when the speed of the drive is used as the control variable the advantage of this scheme is that in the case of normal compression, the course of the kinetic energy be designed in the moving parts via the press path can that the loads especially in the camps lower is held as possible with a sequential control is. Instead of the speed of the drive come as a controlled variable also the force to be applied - with a hydraulic drive also the hydraulic pressure - and the torque to be applied as well as the average electrical current in question.

• die Antriebssteuereinrichtung hat eine Störungserfassungseinrichtung;
• die Störungserfassungseinrichtung weist einen Istwertaufnehmer auf;
• der Istwertaufnehmer ist für die Erfassung einer physikalischen Größe als Istwert geeignet, welche mit dem Verpressungswiderstand korreliert;
• in der Störungserfassungseinrichtung ist wenigstens ein Grenzwertverlauf festgehalten;
• die Störungserfassungseinrichtung weist eine Störungsvergleichseinrichtung auf, die bei einer Verpressung eine Überprüfung darauf hin vornimmt, ob der jeweilige Istwert auf der zulässigen oder nicht zulässigen Seite des zugehörigen Grenzwertverlaufs liegt;
• zu der Störungserfassungseinrichtung gehört eine Signaleinrichtung und/oder eine Abschalteinrichtung für den Antrieb, welcher angesteuert wird bzw. werden, wenn der Istwert auf der unzulässigen Seite des Grenzwerts liegt.

A particular advantage of the sequence control according to the invention is that it opens up the possibility of detecting larger disturbances which can result in incorrect pressing. For this, the pressing device according to the invention is designed as follows:

• the drive control device has a fault detection device;
• the fault detection device has an actual value pickup;
• the actual value sensor is suitable for the acquisition of a physical quantity as an actual value, which correlates with the pressing resistance;
• at least one limit value curve is recorded in the fault detection device;
• the fault detection device has a fault comparison device which, during pressing, checks whether the respective actual value lies on the permissible or impermissible side of the associated limit value curve;
• The fault detection device includes a signal device and / or a shutdown device for the drive, which is or will be activated if the actual value is on the impermissible side of the limit value.

Preferably at least one is upper and at least one lower limit value curve with formation of a limit value corridor recorded, and if possible in adaptation to the Setpoint curve. These can also be constant limit values his. However, it is preferable that the limit value curves the course of the actual value with trouble-free pressing is adapted to form a limit corridor.

The basic idea of this training is, therefore, at a pressing device of the generic type a fault detection device to be provided if there is a deviation physical correlating with the compression resistance Size from a normal course to a signal formation and / or leads to a shutdown of the drive. Thereby the signal formation optically or acoustically, in the simplest way Form as an alarm or blinking of an alarm light or Alarm buzzer, but also depending on the type of fault in a differentiated Signaling up to a display with readable Malfunction report or in the form of a voice output. The operator gets a more or less specified Information that there is a fault and that is why interrupt the pressing process for the purpose of further checking shall be. Instead, or in combination with the signaling can also automatically switch off the Drive done so that the pressing process at least not without further can be continued. It is understood that by the fault detection device according to the invention gained significantly higher security against incorrect pressing is what with a view to the great harm potential of such Mispressing is extremely important.

The choice of the physical correlating with the pressing resistance Size expediently happens in adaptation to that Behavior of the drive. The acquisition of the Speed of the drive, since it deals with the compression resistance changes. For example, there is a blockage of the drive before the end of the press path due to wrinkling on Press fitting or by foreign objects, leaves the speed down the permissible limit corridor, it being in these In cases it is advisable to control the shutdown device. A significant reduction in speed when leaving the Limit corridor also has the pressing one for the Press jaws to large press fittings result. Conversely, increases the speed when a press fitting that is too small acts the pipe end is not pushed far enough into the press fitting becomes or there is a break.

Instead of the speed, it can also be used as a physical quantity the force to be applied, for example by means of strain gauges, be recorded or - analogously - the torque to be applied. Finally, the average electrical current is suitable as an indicator of the resistance to compression, because that too changes with this.

In a further embodiment of the invention it is provided that at least one further upper and / or lower limit value curve is or are recorded on the inadmissible side of the first limit value curve or lie. So there will be a narrower and a wider limit corridor formed that can be used to Signal device and the shutdown device in dependence to control which limit corridor to the impermissible Side is left. For example, can be provided be, when leaving the narrower limit corridor only the Control signaling device and only when leaving the wider corridor the shutdown device. The wider limit corridor should be designed so that it Not pressing too small or too large press fittings is left, but only, for example, in the event of a break or a blockage, i.e. a comparatively heavy one Disorder.

According to the invention it is further provided that via the signaling device different signals can be generated and that the limit value curve or at least one limit value curve via the pressing path - or correlating to this the pressing time - in Areas is divided, with each area having a specific Signaling is assigned. This can take into account the circumstance that certain disorders are usually only borne occur in certain areas. This creates a wrinkle of the press fitting or a blockage Foreign parts or dirt usually only at the end of the press out. The pressing of a press fitting that is too large leads to this an increase in the compression resistance very early, while pressing a press fitting that is too small a long idle phase at high speeds and when hitting one on the press fitting compared to the pressing a suitable press fitting relatively low speed reduction has the consequence. By dividing the areas accordingly the operator receives specific information about the malfunction, which is very reliable and its elimination can then be done in a targeted manner.

It is further proposed that a locking device to block the drive when the shutdown device is activated is provided, the locking device only after Activation of a special unlocking device can be overcome is. This training is intended to prevent an interrupted Pressing only by pressing the on / off switch again is started. The unlocking device can also serve the intended for repressing Select the setpoint curve and, if necessary, the appropriate limit curve.

It when the controlled variable with the physical quantity that correlates with the compression resistance, is identical. In that case, the limit value curves for the physical quantity particularly close to the setpoint curve be adjusted because the regulation ensures that the control corridor is normally not left. On in this way a fault that can no longer be corrected becomes relative quickly grasped, especially when the control limits with the limit value curves for the physical quantity identical, i.e. control corridor and that of the limit value curves included corridor are congruent. This Particularly appropriate training makes saving more special Limit value curves can be dispensed with. The scheme should then be set so that certain deviations, such as for example in the case of tolerances, fluctuations in the coefficient of friction or tension, corrected, but that the serious disturbances, such as B. the pressing not suitable for the press jaws Press fittings or the occurrence of breaks or blockages, can no longer be corrected, so that the Actual value of the controlled variable leaves the control corridor with the consequence that the signaling device and / or the shutdown device is controlled.

In the generic pressing devices, the pressing tools are usually interchangeably attached to the drive member the drive part for the pressing of press fittings and pipes to be able to use different diameters. there are also interchangeable among pressing tools in this sense Press jaws within press jaw carriers - to understand. On however, the only setpoint curve is not for all pressing tools optimal. The same applies to the limit value curves. In principle, therefore, several setpoint curves and gff. Limit value profiles defined, in particular stored be, expediently so that for each type of press tool adjusted target value profiles and limit value profiles if necessary are set.

In addition, it can be useful to change the setpoint curves and if necessary, the limit value curves for different properties of the workpieces. To make an automatic selection from the saved setpoint curves and, if applicable, the limit value curves to be able to make, the pressing device Material sensor, for example in the form of an eddy current sensor, to record the material of the workpieces. In this way, the use of the pressing device is not only on the pressing of workpieces of a certain material limited, but can also be used for other materials are softer or harder and therefore have a different compression resistance have, are needed.

Because the number of types of press fittings and pipe ends is common is not large, it may be sufficient that one manually operated switch arrangement for setting the Setpoint curve and possibly the associated limit curve is provided. It is particularly advantageous if the drive control device is a self-adaptation device over which at least one setpoint curve and optionally the associated limit value curves on the actual Compression resistance is or are adaptable. Such Self-adaptation devices are in the control technology itself known. They enable a specific setpoint course and, if applicable, the associated limit value curves in principle parallel in adaptation to the actual compression resistance postponed by making a test injection becomes. The self-adaptation device provides this test pressing the deviation from the stored Setpoint curve and sets the deviating values to the Place the previously saved values for the setpoint curve.

The self-adaptation device of Can be activated by hand so that self-adaptation only occurs when a test injection is carried out. To this This prevents incorrect setpoint curves or Limit value curves can be saved. The self-adaptation facility can be especially related to customization to other materials or wall thicknesses of press fittings and pipe end as well as for calibration in a new pressing device can be used advantageously.

According to a further feature of the invention it is provided that at least one setpoint curve for the full press travel and for at least one more of these or each of these setpoint curves Setpoint curve for a partial press travel after an interruption of the pressing process are recorded. In this way can an interrupted pressing process with a different setpoint curve to be continued, the better of the circumstances after partial compression is adjusted in the sense that the loads on the parts subject to force are as low as possible being held. It is understood that for each press tool a plurality of such setpoint curves are stored can be, depending on the the interruption of the pressing process already traveled. By means of a corresponding distance or time recording the associated setpoint curve is automatically selected. In the process, limit value profiles are adapted to this setpoint value profile assigned so that even after an interruption Pressing a fault detection adapted to the new setpoint curve he follows.

In a simple version, a switch arrangement that can be operated by hand can be used for setting the respective limit value curves and, if necessary, setpoint curves can be provided. In this In this case, however, operating errors cannot be ruled out. From It is therefore an advantage if it derives from DE-U-297 03 052.3 basic idea of the present invention in the sense is used that the press tool a coding over which the associated limit value curves and possibly the associated setpoint curve can be selected. This poses sure that after replacing the press tool suitable limit value curves and - if a controller or Regulation of the drive is provided, including the setpoint curve to be selected. The coding can be used as a electrical or electronic component be formed, that with the drive device via a transmission link connected is. Examples can be found in DE-GM 297 03 052.3. In particular, a memory chip comes in as coding Question because in it a variety of different encodings can be saved. There is also the possibility a suitable setpoint curve and, if necessary, one Limit value curve or several limit value curves in this Capture memory chip. The memory chip can then Connection of the pressing tool with the drive part of the pressing device as part of the drive control. alternative however, there is also a facility for transmitting the Setpoint curve and possibly the limit curve in the drive control device in question.

Such a memory chip can also be used to press path or characteristic for the pressing tool in question similarly to save the pressing time. When reached the end of the press path or end of the press time can then be an optical one or emitted an acoustic signal and / or the drive was switched off become.

Alternatively, it can be provided that the pressing tool has a position sensor and that in the memory chip a partial press path or a partial press time is stored, wherein the drive is controlled so that only the Partial press travel is carried out when the position sensor is activated becomes. The press path or the partial press path can for one certain size of the press tool can be set. Appropriately it is, however, the press path or partial press path at each Press tool to determine experimentally and the relevant Store value in the memory chip. That way secured that the pressing tool up to its final pressing position, however, it does not go beyond, namely regardless of within the manufacturing tolerances Deviations.

In order to be able to reliably record the press travel, a Start sensor for recording the initial position of the press tool and a distance and / or time sensor is provided his. In particular, a revolution counter is used as the displacement sensor suitable.

Figur 1

den Antriebsteil eines Preßgeräts im Längsschnitt;

Figur 2

den oberen Teil des Antriebsteils gemäß Figur 1 mit einem teilweise dargestellten Preßwerkzeug;

Figur 3

das Preßwerkzeug gemäß Figur 2 in vergrößerter Darstellung;

Figur 4

eine vereinfachte Darstellung der Steuerung des Preßgeräts gemäß den Figuren 1 bis 3 und

Figur 5

eine Grafik zur Veranschaulichung der Drehzahlregelung für die Steuerung gemäß Figur 4.

In the drawing, the invention is illustrated in more detail using an exemplary embodiment. Show it:

Figure 1

the drive part of a pressing device in longitudinal section;

Figure 2

the upper part of the drive part according to Figure 1 with a press tool partially shown;

Figure 3

the pressing tool according to Figure 2 in an enlarged view;

Figure 4

a simplified representation of the control of the pressing device according to Figures 1 to 3 and

Figure 5

4 shows a graphic to illustrate the speed control for the control according to FIG. 4.

The pressing device 1 shown in Figures 1 to 3 is in two parts constructed and consists essentially of a drive part 2 and a pressing tool 3. Both are over one Coupling bolt 4 connected to one another in an articulated manner.

An electric drive motor is located in the drive part 2 5 with a drive shaft 6, which is in a bearing 7 is stored. A drive pinion 8 is arranged at the free end, that meshes with a gear 9, which on an intermediate shaft 10 sits. The intermediate shaft 10 is in the bearings 11 and 12 rotatably mounted. It carries a pinion 13, which meshes with a gear 14, which is part of a spindle nut 15 is. The spindle nut 15 is axially immovable in the bearings 16, 17 stored. The spindle nut 15 is one Spindle 18 passes through, the drive motor 5 removed lying end is provided with a clevis 19. spindle nut 15 and spindle 18 mesh in such a way that at Rotation of the spindle nut 15 an axial displacement of the Spindle 18 is effected. The spindle 18 becomes non-rotatable guided.

In the fork head 19, two drive rollers 20, 21 are free rotatably mounted. The drive rollers 20, 21 are located on the circumference to each other.

The drive shaft 6 also protrudes at the rear end of the drive motor 5 out and is also stored there in a bearing 22. It carries a speed sensor 23 over its scope magnets 24 are distributed at equal intervals. The speed sensor 23, a speed sensor 25 is arranged opposite the device, the magnetic fields emanating from the magnets 24 is able to detect and send appropriate signals to a here only schematically shown control device 26. The signals are counted there, with the number determined the number of revolutions and thus that of the spindle 18 or the fork head 19 corresponds to the distance traveled. Of the there is also a time interval between two signals a measure of the instantaneous speed of the drive motor 5th

The drive part 2 has a housing 27 which is the pressing tool 3 down into a holding fork 28 with two congruent Fork arms 29, 30 that leak such a distance have that the clevis 19 can move between them. The front fork arm 29 is omitted in FIG. 3.

The pressing tool 3 shown in Figures 2 and 3 has two congruent support plates arranged one behind the other on, of which here only the front-side support plate 31 see is. Both support plates 31 have the same T-shape and project into the space with their drive-side areas between the fork arms 29, 30 and sit there on the coupling pin 4. The support plates 31 are spaced to each other and are connected to one another via bearing bolts 32, 33. On each of the bearing bolts 32, 33 there is a press jaw lever 34, 35 - the press jaw lever 34 is omitted in Figure 2 - Which are mirror images and also assume a position in the mirror. The press jaw levers 34, 35 have drive arms 36, 37 going to drive part 2 and upward jaw arms 38, 39. The drive arms 36, 37 have drive surfaces 40, 41, which are during a pressing process cooperate with the drive rollers 20, 21. The bakken arms 38, 39 have on opposite sides semicircular recesses molded into the contour of press jaws 42, 43.

In Figure 2, the press jaw lever 35 - just like that is not shown press jaw lever 34 - pivoted in the open position, so that the drive arms 36, 37 in the space between the fork arms 29, 30 and the press jaws 42, 43 have the greatest possible distance from each other. Between Press jaw levers 34, 35 are inserted one into the other Pipe end 44 and - outside - a press fitting 45 with his radially projecting annular bead 46. The annular bead 46 lies at the level of the press jaws 42, 43 and is intended to pivot the press jaw lever 34, 35 radially inwards under plastic deformation of itself and the pipe end 44 to be pressed.

A pressing process is - starting from that shown in Figure 2 Position - initiated by the drive motor 5 by means of an on / off switch that can be operated from the outside is set. The rotary motion emanating from it is in the Spindle nut 15 in a sliding movement of the spindle 18th implemented, in such a way that the clevis 19 in Direction is moved to the press tool 3. To the plant the drive rollers 20, 21 on the drive surfaces 40, 41 an empty path is bridged first. Because of the slant the drive shafts 40, 41 then become the drive arms 36, 37 spread apart, and the drive rollers 20, 21 drive into the ever-opening space between the drive arms 36, 37. This in turn has Consequence that the jaw arms 38, 39 and thus the press jaws 42, 43 approach each other with compression of the annular bead 46 of the press fitting 45 and the pipe end 44. Figure 3 shows the final pressing position in which the drive rollers 20, 21 are maximally extended and the front sides of the bakken arms 38, 39 have come to rest (in Figure 3 are Press fitting 45 and pipe end 44 not shown).

The control device 26 works with a limit switch 47 together, which is arranged on the outside of the fork arm 29 is. The limit switch 47 has a switch arm 48 which with an actuating projection 49 on the drive arm 37 of the press jaw lever 35 cooperates. The actuation projection 49 presses the switch arm 48 in the open position shown in Figure 2 the press jaw lever 34, 35 in a position in which he the control device 26 signals that the press jaw lever 34, 35 in the initial position, i.e. H. open position are located. From here, the control device can 26 a distance measurement via the speed sensor 23 and the speed sensor 25. Instead of a distance measurement can also a time measurement can be initiated.

The drive part 2 of the pressing device 1 can be via the coupling bolt 4 - it is removable - with different sizes can be equipped by pressing tools 3. So that the control device 26 can recognize the type and size of the press tool 3, the pressing tool 3 has a coding, namely in the form of an electrical resistor 50, which in a circuit 51 sits. The resistor 50 can on one protected location of the pressing tool 3 may be arranged. Of the part of the circuit 51 contained in the pressing tool 3 sets itself via spring contacts 52, 53 up to here only as a block symbolized control device 26 continues.

The resistor 50 has one for the respective pressing tool 3 specific resistance value. With a resistance measurement the pressing tool 3 can thus be identified. The resistance measurement takes place with conventional analog-digital converters.

In addition, a jaw closing sensor is located in the circuit 51 54, which is arranged in the right press jaw lever 35. He has a blind bore 55 which leads to the left press jaw lever 34 is open. A tappet 56 is horizontal in the blind bore 55 slidably mounted. It is over a compression spring 57 with a directed towards the left press jaw lever 34 Force applied.

The plunger 56 is in two spaced ring webs 58, 59 in the blind bore 55 out and ends in an electrically insulating Rubber piece 60. In the space between the A contact screw 61 projects into the two ring webs 58, 59. Both the plunger 56 and the contact screw 61 are Part of circuit 51.

In the open position of the press jaw levers 34, 35 are the opposite surfaces of the drive arms 36, 37 spaced. In this way, the plunger 56 is above the opening of the Blind bore 55 with the rubber piece 60 to the outside. Of the Right ring web 59 abuts the contact screw 61, so that the circuit 31 is closed. This is a resistance measurement to identify the press tool 3 based on of the resistance value of the resistor 50 possible.

When closing the press jaw lever 34, 35 it comes in the last pressing phase, but before the final pressing position, for contact of the rubber piece 60 with the opposite one Side of the left jaw arm 38. This causes the tappet 56 moved accordingly against the action of the compression spring 57 with the result that the electrical contact between plunger 56th and contact screw 61 is lost. The circuit 51 will interrupted. This creates a signal in the control device 26 processed in the manner described below becomes.

To detect a wire break in the circuit 51 can parallel to the jaw closing sensor 54 and / or to the resistor 50 a second resistor must be installed, the value of which is clearly differs from resistor 50. In this way becomes a signal confusion with the signal of the jaw closing sensor 54 avoided.

FIG. 4 shows part of the control device 26, essentially those by the dashed box marked drive control device 62. core of the drive control device 62 is a microprocessor 63. It is assigned to it is the drive motor 5 with the speed sensor 25, from which a line 64 goes into the microprocessor 63. Of the Drive motor 5 is powered by a voltage supply line 65 fed, which can be connected to the operating network. In the The voltage supply line 65 is followed by a shutdown element 66, a power control element 67 - here in Form of a triac to reduce performance by phase control - and a motor reversal element 68 for Purpose of determining the direction of rotation. The limit switch 66 are via a line 69, the power control element 67 via a Line 70 and motor reversing element 68 via line 71 electrically connected to the microprocessor 63.

The microprocessor 63 is connected to via a line 72 a manually operated on / off switch 73, via which the drive motor 5 can be started by means of the microprocessor 63 can. The second line 74 is already connected to FIG. 2 described limit switch 47 for the detection of the initial position of the pressing tool 3.

The microprocessor 63 becomes specific via a line 75 Specifications submitted. For one, this is the coding of the Press tool 3 through the resistor 50. On the other hand, this is the jaw lock sensor 54. In addition, there is a selector switch 76 provided, over the manually determined boundary conditions for the work of the drive control device 62 can be predetermined can.

In the microprocessor 63 there are a number of setpoint curves - They can also be referred to as characteristic curves - for example in the form of functions or points for the speed curve saved via the press path. Every setpoint course is specific to a particular press tool 3. At Connection of a specific press tool 3 is through the The above-mentioned check of the resistance 50 is the appropriate one Setpoint curve selected. This setpoint curve is determining for the control of the drive motor 5 via the Power control element 67.

The speed sensor 23, the speed sensor 25 and the associated Line 64 belongs to the control loop of a follow-up control, their command variable the respective setpoint curve and their Control variable are the speed. Of the aforementioned elements becomes a corresponding to the speed of the drive motor 5 Signal given to the microprocessor 63, in which this Signal is processed. In a comparison device of the Microprocessor 63 is checked whether the actual speed value within the control limits of a control corridor and thus within of the permitted range or outside. In the former The case remains with the phase angle specification of the power control element 67 and thus in the performance target. In the latter case, the leading edge is cut by a certain one Amount changed, so that the performance target is reduced if the speed is too high, and increased if the speed is too low.

The scheme is designed so that the one described above Control process under normal conditions for feedback of the actual speed value in the control corridor and if possible leads in the middle area. However, the next comparison found that the actual speed value is still outside of the control corridor, there must be a malfunction. Such faults can, for example, compress one not suitable press fittings, one not completely in the Press fitting inserted pipe end, a break in the drive chain between drive motor 5 and press jaws 42, 43. or a blockage due to jammed Foreign parts or wrinkling on the press fitting 45. Of the Microprocessor 63 then emits a signal which, depending on Art the detected disturbance via line 69 to the limit switch 66 with the result that the drive motor 5 is switched off, and / or via a line 77 to a display 78 is given where the disturbance is appropriately visualized becomes.

The control process described above, for a follow-up control is characteristic, be clearer from FIG. 5 made. In the graphics, the ordinate means the speed of the drive motor 5 and the abscissa the press travel. The at Continuous curve 79 starting from zero shows the schematic Speed curve for a specific press tool 3 below Normal condition. It then essentially corresponds to the associated one stored setpoint history. The press path is in a series of sections of equal width - exemplary with 80 designated - divided. At the section boundaries - exemplary designated 81 - is a target-actual comparison made whether curve 79 is still within of a permissible control corridor - designated 82 by way of example - located. This is the case for curve 79 the case. The control corridors 82 are on the top and bottom by changing from section 80 to section 80 upper and lower control limit values - designated 83 and 84, for example - limited. Form all upper control limit values 83 together an upper control limit curve, while the lower Control limit values 84 taken together form a lower control limit curve represent. It is understood that the Division of the press path into sections 80 in the microprocessor 63 is many times finer, so that an actual-target comparison is carried out correspondingly more often.

In the graphic there is also the speed deviation at different Types of faults are shown. So is the course of the Curve section 85 characteristic of the pressing of a for the respective press tool 3 to large press fittings. Because of of the higher form resistance, the speed drops when leaving of the control corridor 82. The regulation of the leading edge is unable to decrease the speed prevent by higher performance target. Characteristic is furthermore that the speed drop at one point in time or a waypoint where there is a suitable one Press fitting is still an idle stroke.

The curve section 86 is typical for a blockage, since the Speed goes steeply towards zero. For example, it can have a blocking effect a foreign part that moves between the Parts of the pressing tool 3 has come. A similar drop in speed shows curve section 87, but here in End area of the press path. This shows wrinkling the outside of the press fitting 45.

The steeply rising curve section 88 is characteristic for a non-blocking break. There is no resistance the speed increases suddenly.

The curve profile according to curve section 89 arises if a press fitting that is too small for the press tool 3 in question is pressed. The resistance is then so low that the Speed leaves the control corridor 82 upwards and also no longer returned by readjusting the phase angle can be. A similar speed curve then arises a, if the tube 44 is insufficient in the press fitting 45th has been inserted.

The graphic also shows the course in the event of an interruption of the pressing process. In the subsequent After injection, the speed moves according to curve 79. In the end area, the curve runs according to the dashed line Section 90 straight ahead and then bends in the last Section in line with the new one Compression resistance downwards.

For the coding of the press tool 3 can instead of the resistor 50, an electronic memory chip 100 can also be provided be as shown in dashed lines in Figure 4. This memory chip 100 contains one for the one in question Press tool 3 specific coding and is on the line 101 connected to the microprocessor 63.

Instead of coding, a memory chip 100 can also be used for the pressing tool 3 specific setpoint curve stored his. This can be done when coupling the press tool 3 transferred with the drive part 2 in the microprocessor 63 and saved there. Has this training the advantage that the drive part 2 with any type of Pressing tools 3 can be combined since each pressing tool 3 stores the setpoint curve that is specific to him Has. The difference is the combination option if a coding is provided on the in the drive control device 62 stored setpoint curves limited, d. H. the drive part 2 can not with new pressing tools 3 can be combined, which have a performance curve should, whose setpoint curve is not in the drive control device 62 is stored.

The memory chip 100 also contains memory locations for the Storage of a remaining press path provided. This residual press path is obtained through the following calibration process.

The jaw closing sensor 54 is set so that it already responds, ie interrupts the circuit 51 when the bakken arms 38, 39 not quite their final pressing position shown in FIG. 3 achieved. The press tool 3 is then on an appropriate calibration device or with the help of the drive part 2 of the pressing device 1 several times with a specific Force over the full press travel to a final press position, in which the drive arms 36, 37 meet on the end face, moved together. With the help of the speed sensor 24 and the speed sensor 26 and a special program is determined by recording the number of magnetic fields of the speed sensor 24 the residual press path determined by the press lever 34, 35 after the jaw closing sensor 54 has responded still put back. This is repeated until the do not differentiate or only minimally differentiate the measured remaining press paths, the pressing tool 3 has therefore settled. The one after that determined residual press path is stored in the memory chip 100 accepted. It is characteristic of the pressing tool in question 3. Due to manufacturing tolerances Pressing tools 3 of the same size, different residual press paths result.

The calibration described above ensures that the Drive motor 5 in a defined, for that Pressing tool 3 characteristic final pressing position switched off becomes. The jaw closing sensor 54 is released during the pressing process the distance measurement for the stored remaining press path, whereby this by counting the pulses detected by the speed sensor 25 happens. After the remaining press travel has been completed, the drive motor 5 switched off via the switch-off element 66.

Instead of just one remaining press path, several remaining press paths can also be used can be stored by the above-described calibration process under compression of combinations of press fitting 45 and Pipe end 44 is performed, which is the same outer Geometry due to their compression resistance distinguish between different materials and / or wall thicknesses. This results from the elastic behavior in particular the press tool 3 different Restpreßwege. The selection of the associated remaining press path can - with knowledge of the material and the wall thickness of the material to be pressed Press fittings 45 - using the selector switch 76 happen.

Alternatively, an automatic selection of the appropriate one can be made Restpreßweg done in such a way that during the Pressing the compression resistance at a certain Point of the pressing path and its value as a selection criterion is used. This can be the case with the present pressing device 1 happen in such a way that each one is characteristic Deviation from curve 79 found at the specific location and the measure of the deviation as a selection criterion is used. Instead, there is also the possibility an additional actual value sensor for a physical To provide a size that corresponds to the compression resistance, for example in the form of a strain gauge on one loaded part of the press tool 3 or a torque tap on the drive shaft 6.

If in the memory chip 100 or in the microprocessor 63 for each pressing tool 3 several different setpoint curves are saved, which to the different Materials and / or wall thicknesses for the press fitting 45 and the tube end 44 are adapted, when selecting the respective A corresponding setpoint curve in the microprocessor 63 Allocation of the appropriate remaining press path is made automatically become. This applies both in the event that the above Follow-up regulation exists, as well as with a - then feedback-free - sequence control.

It is not necessary that the remaining press path or the remaining press paths be stored in the memory chip 100. Instead there is the possibility of storing the remaining press paths on the drive part 2 and here in particular in the microprocessor 63. In this case, the remaining press path or the group of remaining press paths by coding based on resistor 50 or the memory chip 100 driven. However, then. be assured that for the respective press tool to be connected 3 actually a suitable residual press path or one Group of residual press paths is stored. Comes a press tool 3 for use, for which no residual pressing path or no group of residual press paths is stored, should the calibration process described above - be it using the Drive part 2, be it with the help of a special calibration device - be made up for.

Claims (30)

1. Pressing device (1) for joining work pieces (44, 45) having a press tool (3) and a motor actuated drive (5) for operating the press tool (3) along its press travel and also having a control device (26) which has a drive control device (62) with a power control device (67) as setting element for influencing the drive (5), wherein at least one desired value progression is retained as reference magnitude whereby a setting magnitude corresponding to the desired value progression is produced for influencing the power control device (67), and wherein the power control device (67) and the desired value progression (79), respectively each desired value progression, form part of a follow up regulation with feed back.
2. Pressing device according to claim 1, characterised in that the desired value progression (79), respectively each desired value progression, is confined within a regulating corridor (82) having upper and lower regulating limits (83, 84) defining the regulating band width.
3. Pressing device according to claim 1 or 2, characterised in that the rotational speed of the drive (5) is the regulating magnitude of the follow up regulation.
4. Pressing device according to one of claims 1 to 3, characterised by the following features

   the drive control device (62) has an error detecting device;

   the error detecting device has an actual value pick-up (23, 24, 25);

   the actual value pick-up (23, 24, 25) is appropriate for detecting a physical magnitude as actual value which correlates with the pressing resistance;

   at least one limit value progression (83, 84) for the actual value is retained in the error detecting device;

   the error detecting device has a comparator device which during pressing carries out a check as to whether the current actual value lies on the permissible or the not permissible side of the related limit value progression (83, 84);

   to the error detecting device belongs a signalling device (78) and/or a shut down device (66) for the drive (5), which is or are activated if the actual value lies on the not permissible side of the related limit value.
5. Pressing device according to claim 4, characterised in that at least one upper and at least one lower limit value progression (83, 84) are retained.
6. Pressing device according to claim 5, characterised in that at least one limit value progression (83, 84) is matched to the desired value progression with formation of a limit value corridor.
7. Pressing device according to claim 6, characterised in that at least one further upper and/or lower limit value progression is or are retained which respectively lies or lie on the not permissible side of the first limit value progression (83, 84).
8. Pressing device according to claim 7, characterised in that, if the actual value lies on the not permissible side of the first limit value progression (83, 84) but still lies on the permissible side of the adjoining further limit value progression, then the signalling device (78) is activated, and that if the actual value also lies on the not permissible side of the further limit value progression, then the shut off device (66) is activated.
9. Pressing device according to one of claims 4 to 8, characterised in that the limit value progression, respectively at least one limit value progression (83, 84), is sub-divided into sections (80) along the press travel whereby one specific signalling indication is allocated to each section (80).
10. Pressing device according to one of claims 4 to 9, characterised in that an inhibitor device for blocking the drive (5) upon activation of the shut down device (66) is provided and the inhibitor device can be overcome only after actuation of a specific un-inhibiting device.
11. Pressing device according to one of claims 4 to 10, characterised in that the regulating magnitude of the follow up regulation is identical to the physical magnitude which correlates with the pressing resistance.
12. Pressing device according to at least claim 2 and 4, characterised in that the regulating limits (83, 84) are identical to the limit value progressions (83, 84).
13. Pressing device according to one of claims 4 to 12, characterised in that a plurality of desired value progressions, and if appropriate a plurality of limit value progresions (83, 84), are set.
14. Pressing device according to claim 13, characterisd in that the desired value progressions, and if appropriate the limit value progressions (83, 84), are matched to press tools (3) of different sizes.
15. Pressing device according to claim 13 or 14, characterisd in that the pressing device (1) has a material sensor for detecting the material of the workpieces (44, 45) wherein selection of the desired value progression, and if appropriate of the limit value progressions (83, 84), is carried out by way of the material sensor.
16. Pressing device according to claim 15, characterisd in that the desired value progressions, and if appropriate the limit value progressions (83, 84), are determined for different properties of the workpieces (44, 45).
17. Pressing device according to one of claims 14 to 16, characterised in that a hand operated switching device (76) is provided for setting the desired value progression (79) and if appropriate the current limit value progressions (83, 84).
18. Pressing device according to one of claims 1 to 17, characterised in that the drive control device (62) has a self adaptation device for matching at least one desired value progression (79), and if appropriate the related limit value progressions (83, 84), to the actual pressing resistance.
19. Pressing device according to one of claims 1 to 18, characterised in that the desired value progression (79), respectively each desired value progression, have allocated to them further corresponding matching desired value progressions (90), and if appropriate limit value progressions, for a partial pressing.
20. Pressing device according to claim 19, characterised in that the desired value progression (90), respectively desired value progressions, for the partial pressing is or are allocated automatically to the desired value progression (79), respectively the desired value progressions, for the full pressing upon selection of the latter.
21. Pressing device according to one of claims 1 to 19, characterised in that the press tool (3) has a coder (50, 100) for determining related desired value progression (79) and if appropriate the related limit value progressions (83, 84).
22. Pressing device according to claim 21, characterised in that the coder is constructed as an electrical or electronic component (50, 100) connected to the drive control device (62) by way of a transfer element.
23. Pressing device according to claim 21, characterised in that the coder is constructed as a memory chip (100) with at least one desired value progression (79) stored therein.
24. Pressing device at least according to claim 4 and 23, characterised in that the related limit value progressions (83, 84) are also stored in the memory chip (100).
25. Pressing device according to claim 23 or 24, characterised in that a device is provided for loading into the drive control device (62) the desired value progression (79), respectively desired value progressions, and if appropriate the limit value progressions (83, 84), respectively stored in the memory chip (100).
26. Pressing device according to one of claims 23 to 25, characterised in that the press travel or a pressing time is stored in the memory chip (100) and that upon reaching the end of the press travel, respectively the end of the pressing time, a visual or accoustic signal is emitted and/or the drive (5) is shut down.
27. Pressing device according to one of claims 23 to 25, characterised in that the press tool (3) has a position pick-up (54) and that in the memory chip (100) there is stored the remaining press travel, respectively the remaining pressing time, whereby the drive (5) is controlled such that movement is confined to the remaining press travel, respectively the remaining pressing time, while the position pick-up (54) is activated.
28. Pressing device according to one of claims 1 to 27, characterised in that a start pick-up (47, 48, 49) is provided to detect the start position of the press tool (3).
29. Pressing device according to one of claims 1 to 28, characterised in that the control device (26) has a travel pick-up and/or time pick-up (23, 24, 25) for the pressing process.
30. Pressing device according to claim 29, characterised in that the travel pick-up is constructed as a rotation counter (23, 24, 25).

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