EP0860220B1 - 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 influencing the drive.

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 the one below 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 the pressing tool (DE-U-296 02 240.3).

The aim of every pressing is to avoid incorrect pressing, since they are usually a leaky pipe connection for As a result, what is great with liquid-carrying pipelines Can cause damage. Incorrect grouting can be different Have causes, these causes with the known Most of the pressing devices cannot be detected, incorrect pressing caused by such a cause so it goes unnoticed.

Such a case exists when a pressing device with a certain pressing tool for pressing a press fitting is used that does not fit the press tool, so is either too big or too small. In both cases comes this leads to incorrect grouting, which leads to leaks can. The mispressing cannot be noticed because both the final force and the final pressing position are reached becomes.

It can also lead to wrinkling in the area of the end faces two adjacent press jaws come. Since they mostly End of the press path occurs, it is by the operator hardly noticed, especially when the pressing device has a force limiting element off. Small folds can too then not be noticed if a limit switch is provided is, especially if the limit switch in the area two press jaws is arranged where no wrinkling occurs. The same applies if the Press tool foreign objects such as dirt or other solid Nest parts that block the movement of the press jaws.

Incorrect pressing can also occur if one end of the pipe is insufficiently inserted into the press fitting. at Pressing devices that do not have a special monitoring element for this this also goes unnoticed and usually has one Incorrect pressing results.

Furthermore, it can happen that it is in the power Parts of the drive break. This can result in a sudden increase in speed, whereby there is a danger from the pressing device.

The interruption of a pressing process poses a special problem for example due to a power failure Post-grouting is a long free path to overcome, which takes time costs and depending on the control of the drive to build high kinetic energies with the risk of sudden impact the press jaws on the only partially pressed press fitting to lead.

In EP-A-0 291 329 there is a stationary press machine disclosed for crimping cable lugs. At this Press machine is the pressing force during the pressing process recorded and the resulting press force curve after the pressing process with a reference short compared. Are the deviations between the two curves too large, a signal is generated, the type of signal allows a conclusion to be drawn on the nature of the pressing error. The disadvantage here is that the pressing process also a faulty pressing is initially carried out to the end, before making a comparison. This can be too high Loads on the pressing tools and the drive up to Cause damage.

The invention has for its object a press of the type mentioned in such a way that incorrect pressing avoided with higher reliability or at least can be recognized.

• die Antriebsteuereinrichtung 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 Störungseinrichtung weist eine Störungsvergleichseinrichtung auf, die während des Verpressvorgangs ständig 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, sobald der Istwert auf der unzulässigen Seite des Grenzwerts liegt.

This object is achieved according to the invention by a pressing device with the following features:

• 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 device has a fault comparison device which constantly checks during the pressing process whether the respective actual value lies on the permissible or non-permissible 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 as soon as 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. These can also be constant Limit values. However, it is preferable that the limit value curves to the course of the actual value with trouble-free Adjustment adapted to form a limit corridor is.

The basic idea of the invention is therefore in a pressing device the generic type a fault detection device to be provided if there is a deviation with the compression resistance correlating physical size of one Normal course for a signal formation and / or a shutdown of the drive leads. The signal formation can be optical or acoustically, in the simplest form as Alarm signaling or flashing of an alarm lamp or alarm buzzer, but also depending on the type of disorder in a differentiated Signaling up to a display with a readable fault message or in the form of a speech. The operator receives more or less specified information that there is a malfunction and that therefore the pressing process be interrupted for the purpose of further review should. Instead, or in combination with signaling the drive can also be switched off automatically, so that the pressing process at least not easily can continue. It is understood that the inventive Fault detection device an essential higher security against mispressing is gained what with a view to the great damage 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. For drives that are not power-controlled the detection of the speed of the Drive since it changes with the compression resistance. If the drive is blocked, for example before the end of the press path due to wrinkling on the press fitting or by foreign objects, the speed leaves the permissible limit corridor down, being in this 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 too large press fittings. Conversely, it increases Speed if a press fitting that is too small is applied, 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.

In a further embodiment of the invention it is provided that Different signals can be generated via the signal device and that the limit value curve or at least one limit value curve via the press path - or correlating to that Pressing time - divided into areas, each area a specific signal is assigned. This can the fact that certain disturbances are taken into account usually only occur in certain areas. So results there is a wrinkling of the press fitting or a blockage due to foreign parts or contamination towards the end of the press. The pressing of a press fitting that is too large on the other hand leads to an increase in compression resistance very early on, while squeezing one too small Press fittings have a long idle phase at high speeds and when hitting the press fitting one compared to the Pressing a suitable press fitting relatively low speed reduction has the consequence. By appropriate division of the areas, the operator receives specific information about the fault, which is very reliable and whose Elimination can then be done in a targeted manner.

It is particularly advantageous if the fault detection device according to the invention with a power control device is combined as part of the drive control device, whereby at least one setpoint curve is recorded as a reference variable , via which one corresponds to the setpoint curve Control variable for influencing the power control device is produced. Such a drive control device is in DE-U-297 03 052.3 with reference to the unpublished German patent application 196 33 199.4 disclosed. This can drive the performance in the way be limited that the press tool at least to the end of the press has a lower 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 Maximum force is.

In a simple version, the setpoint course can be in two stages be in such a way that in the first phase of the press path and here a small one, especially when overcoming the free travel Performance is specified, which is then applied to the Press fittings in adaptation to the resulting compression resistance is increased. By storing a variety of control parameters - for example in the form of a table However, the setpoint curve can be very close adapted to the course of the compression resistance in the manner be that the stress on the power Parts of the pressing device, for example when the Press jaws on the press fitting and especially at the end of the Press way, and thus the creeping changes as a result Wear can be kept low. In connection with the Fault detection device according to the invention can each by location and type of change in the physical detected The size of the faults is recorded relatively precisely and also differentiated can be specified.

The power control device and the setpoint curve or the setpoint curves can be part of a sequence control be designed without feedback. Here, the power control device gets according to a desired course the physical quantity associated with the compression resistance correlated, a performance target - for example by adjusting the leading edge in a triac as Power control or pulse width modulation at one Transistor - which at normal compression to a adapted course leads. However, it is more advantageous if instead of a sequential control a sequential control with Feedback is provided in which the setpoint curve or each setpoint course from a defining the control bandwidth Control corridor with upper and lower control limits is included. With the help of such a follow-up arrangement a desired course can then also be carried out within narrow limits hold when minor disturbances occur, such as Voltage fluctuations or different coefficients of friction on Press fitting. Tolerances can also be found on the press tools as well as creeping changes due to wear or Compensate for pollution.

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 make the loads lower, especially in the bearings is held as possible with a sequential control is. The pressing process is independent, for example of voltage changes on the input side or changes in the coefficient of friction in the bearings, on the press jaws or on the press fitting even because they are regulated by the control loop. The course of the setpoint should preferably be represented by a Control corridor with upper and lower control limits be fixed.

Both with the sequential control and with the sequential regulation come along as a variable correlating to the compression resistance the speed of the drive also the force to be applied - with a hydraulic drive also the hydraulic pressure - and that torque to be applied and also the average electrical Electricity in question. It is particularly advantageous if the controlled variable with the physical size, with the compression resistance correlated, is identical. In that case, the Limit value curves for the physical quantity very closely to the Setpoint curve can be adjusted, because the control ensures that the control corridor does not normally leave becomes. In this way, a fault that can no longer be corrected detected relatively quickly, especially if the control limits with the limit value curves for the physical Size identical, so the standard corridor and that of the Threshold values included corridor congruent are. This particularly useful training makes the storage special limit value curves can be dispensed with. The regulation should then be set so that certain deviations, such as tolerances, friction coefficient or voltage fluctuations are corrected, but that disorders described above, such as. B. pressing press fittings not matching the press jaws or the appearance broken or blocked, no longer corrected can be, so that the actual value of the controlled variable the control corridor with the result 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 To understand press jaws within press jaw carriers. On however, the only setpoint curve is not for all pressing tools optimal. The same applies to the limit value curves. In principle, therefore, there should be several limit value curves and if necessary, setpoint curves defined, in particular stored be, expediently so that for each type of press tool adapted limit value profiles and, if necessary, set value profiles are set.

In addition, it may be appropriate to change the limit value curves and if necessary, the setpoint curves for different properties of the workpieces. To make an automatic selection the stored limit value curves and, if applicable, the setpoint 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 switching arrangement for setting the Setpoint curve and any associated limit curves is provided. It is particularly advantageous if the Drive control device a self-adaptation device over which the limit value curves and, if applicable also the setpoint curve for the actual compression resistance is or are adaptable. Such self-adaptation facilities are known per se in control engineering. they allow es, the limit value curves and, if applicable, the associated setpoint curve in principle in parallel in adaptation to shift to the actual compression resistance, by performing a test injection. With this test pressing the self-adaptation device provides the deviation of the stored limit value curves and puts the deviating values in the place of the previously saved ones Values.

The self-adaptation device of Can be activated by hand, so that self-adaptation only then is possible if a test injection is carried out. On in this way it is avoided that erroneous limit value profiles or setpoint curves can be saved. The self-adaptation facility can be especially related to the adjustment to other materials or wall thicknesses of press fittings and pipe end as well as for calibration on a new one Press 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. With 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 the limit value curve or the limit value curves as well if necessary, a suitable setpoint curve in this memory chip hold. The memory chip can then connect of the pressing tool with the drive part of the pressing device as Part of the drive control can be designed. Alternatively comes however also a device for transferring the limit value curves and possibly the setpoint curve in the drive control device in question.

Such a memory chip can also be used to press path characteristic for the press tool in question - or 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 a further embodiment of the invention it is proposed that a locking device to block the drive Control of the shutdown device is provided, the Locking device only after activating a special unlocking device can be overcome. This training is intended to prevent that an interrupted pressing process only druch actuating the on / off switch again becomes. The unlocking device can also be used for the post-injection provided limit value curves and if necessary select the appropriate setpoint curve, and also additionally in adaptation to the until the interruption of the pressing process Press path covered. To capture the latter too should be a starting sensor to record the starting position of the pressing tool and a distance and / or time sensor be provided. In particular, as a displacement sensor a revolution counter is 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 can be installed, the value of which clearly different from the resistance 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 Shape of a transistor for the purpose of effecting a reduction in performance through pulse width modulation - and a motor reversing element 68 for the purpose of determining the direction of rotation. The limit switch 66 are the power control element 67 via a line 69 via a line 70 and the motor reversing element 68 via a 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 a return 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 malfunctions can include pressing a 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 (33)

1. Pressing device (1) for joining workpieces (44, 45), comprising a press tool (3) and a motor drive for operating the press tool (3) via a press course as well as a control device (26) with a drive control device (62) for acting on the drive (5), characterised by the following features:

   the drive control device (62) includes an interference detecting device;

   the interference detecting device comprises a nominal value pickup (23, 24, 25);

   the nominal value pickup (23, 24, 25) is suitable for determining a physical value as nominal value which correlates with the compression resistance;

   in the interference detection device is stored at least one threshold value course (83, 84) for the nominal value;

   the interference detection device comprises a comparative device which during a compression process continuously checks if the respective nominal value lies within a admissible or not admissible side of the associated threshold value course (83, 84);

   the interference device includes a signalling device (78) and/or a switch-off device (66) for the drive (5) which is/are operated as soon as the nominal value lies on the inadmissible side of an associated threshold value.
2. Pressing device according to Claim 1, characterised in that at least one upper and at least one lower threshold value course (83, 84) are stored.
3. Pressing device according to Claim 2, characterised in that at least one threshold value course (83, 84) is matched to the course of the nominal value during interference-free compression whilst establishing a threshold value corridor.
4. Pressing device according to Claim 3, characterised in that at least one further upper and/or lower threshold value course (83, 84) is/are stored which lie(s) respectively on the inadmissible side of the first threshold value course.
5. Pressing device according to Claim 4, characterised in that the signalling device (78) is actuated when the nominal value lies on the inadmissible side of a first threshold value course (83, 84) but still on the admissible side of an adjacent further threshold value course, and the switch-off device (66) is actuated when the nominal value also lies on the inadmissible side of the additional threshold value course.
6. Pressing device according to one of Claims 1 to 5, characterised in that the threshold value course or at least one threshold value course (83, 84) are over the press course divided into sections (80), and each section (80) is associated with a specific signal command.
7. Pressing device according to one of Claims 1 to 6, characterised in that the drive control device (62) comprises an output control device (67) as control member, and at least one nominal value course (79) is stored as a guide value by means of which a control value, which corresponds with the nominal value course, is established for affecting the output control device (67).
8. Pressing device according to one of Claims 1 to 7, characterised in that the output control device (67) as well as the nominal value course(s) are parts of a follow-up control.
9. Pressing device according to Claim 8, characterised in that the physical value which correlates with the compression resistance is/are revolutions of the drive (5), load to be applied, torque to be applied and/or electric current delivered to the drive (5).
10. Pressing device according to Claim 7, characterised in that the output control device (67) and the nominal value course(s) (79) are part of a follow-up control.
11. Pressing device according to Claim 10, characterised in that the control value of the follow-up control is the revolution of the drive (5).
12. Pressing device according to Claim 10 or 11, characterised in that the control value of the follow-up control is identical to the physical size which correlates with the compression resistance.
13. Pressing device according to one of Claims 10 to 12, characterised in that the nominal value course (79) or each nominal value course is locked in by a control corridor (82), which defines the control band width with upper and lower control limits (83, 84).
14. Pressing device according to Claim 13, characterised in that the control limits (83, 84) are identical to the threshold value courses (83, 84).
15. Pressing device according to one of Claims 1 to 14, characterised in that a plurality of threshold value courses (83, 84) and, if appropriate, a plurality of nominal value courses (79) are determined.
16. Pressing device according to Claim 15, characterised in that the threshold value courses (83, 94) and, if appropriate, the nominal value courses (79) are matched to press tools of different sizes.
17. Pressing device according to Claim 15 or 16, characterised in that the pressing device (1) comprises a material sensor for detecting the material of the workpieces (44, 45), and a selection of threshold value courses (83, 84) and, if appropriate, of the nominal value course (79) is made via the material sensor.
18. Pressing device according to Claim 16, characterised in that the threshold value courses (83, 84) and, if appropriate, the nominal value courses (79) are determined for different properties of the workpieces.
19. Pressing device according to one of Claims 16 to 18, characterised in that a manually operated switch arrangement (76) is provided for setting respective threshold value courses (83, 84) and, if appropriate, the nominal value course (79).
20. Pressing device according to one of Claims 1 to 19, characterised in that the drive control device (62) comprises a self-adapting device by means of which the threshold value courses (83, 84) and, if appropriate, the nominal value course (79) is/are matchable to the actual compression resistance.
21. Pressing device according to one of Claims 1 to 20, characterised in that the nominal value course (79) or each nominal value course is/are associated with respectively matched additional nominal value courses (90) as well as threshold value courses for part compression.
22. Pressing device according to Claim 21, characterised in that the association of the nominal value course(s) (90) for part compression to the nominal value course(s) (79) between the nominal value courses for full compression is performed automatically with their selection.
23. Pressing device according to one of Claims 1 to 22, characterised in that the pressing tool (3) includes a coding (50, 100) by means of which associated threshold value courses (83, 84) and, if appropriate, an associated nominal value course (79) can be determined.
24. Pressing device according to Claim 23, characterised in that the coding is designed as an electrical or electronic module (50, 100) which is connected via a transmission member to the drive control device (62).
25. Pressing device according to Claim 23, characterised in that the coding is designed as a memory chip (100) with at least a therein stored threshold value course (83, 84).
26. Pressing device according to Claim 25, characterised in that the associated nominal value course (79) is also stored in the memory chip (100).
27. Pressing device according to Claim 25 or 26, characterised in that a device for loading of threshold value courses (83, 84) and, if appropriate, nominal value courses (79) as stored in the memory chip (100) is provided in the drive control device (62).
28. Pressing device according to one of Claims 25 to 27, characterised in that the press course or a press time is stored in the memory chip (100) and that an optical or acoustic signal is given and/or the drive (5) is switched off when the press course end or press time end is arrived at.
29. Pressing device according to one of Claims 25 to 28, characterised in that the press tool (3) comprises a position pickup (54) and in the memory chip (100) is stoned a remaining press course or a remaining press time, and the drive (5) is controlled in such a manner that movement is performed only over the remaining press course or the remaining press time when the position pickup (54) is being activiated.
30. Pressing device according to one of Claims 1 to 29, characterised in that a locking device is provided for blocking the drive (5) when the switch-off device (66) is activated, and the locking device can be overcome only after operating a special unlocking device.
31. Pressing device according to one of Claims 1 to 30, characterised in that a start pickup (47, 48, 49) is provided for determining the starting position of the press tool (3).
32. Pressing device according to one of Claims 1 to 31, characterised in that the control device comprises a course and/or time pickup (23, 24, 25) for the pressing process.
33. Pressing device according to Claim 32, characterised in that the course pickup is designed as a revolution counter (23, 24, 25).

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