EP0860222B1 - Pressing device and process for storing the press displacement or remaining press displacement - 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 belongs to a control device and with a storage device. The invention further relates to a method for Storage of the pressing path or the remaining pressing path in the pressing 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 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 inward during the pressing process Formation of a substantially closed press room moves become. The pressing tool is interchangeable on the rest Part of the pressing device 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 one Free travel 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. disclosed on July 31 1997).

Even a jaw lock sensor cannot work under all circumstances guarantee that the drive is exactly in the intended final pressing position is switched off. switching off too early has Consequence that the compression is insufficient, so that it at the Pipe connection can lead to leaks. Switching off too late causes overpressing, causing as a result severe material deformation Cracks or notches occur can the strength and tightness of the pipe joint can also affect. Becomes an overpressing by stops on the pressing tool or by hitting each other prevents the end faces of the press jaws, speaks the jaw closing sensor not on with the result that the press tool strong shock loads as a result of the unbraked striking the press jaws are subject to each other.

In addition, both the press itself and here in particular the press tool as well as the jaw closing sensor manufacturing tolerances. Already slight differences in the dimensioning of those moved by the drive Parts can have significant variations in elastic behavior cause these parts that change the press geometry. Appropriate The game has effects in the camps of the moving Parts.

Another problem arises from the fact that a certain pressing tool only for pressing one Press fittings with a certain diameter is suitable, however, such press fittings made of different hard materials exist and / or have different wall thicknesses can with the result that press fittings of the same size different Have compression resistances. The moving parts of the pressing device are loaded differently accordingly, d. H. the elastic behavior of the loaded parts of the pressing device depends on the type of pipe connection. This too geometries deviate considerably from each other in the area the press jaws. The jaw closing sensor then responds late or early with the risk of pressing is not optimal.

Finally, it should be noted that over time, creeping Changes due to wear, especially in the bearings the moving parts can occur. This also changed the geometry in the area of the press jaws is not insignificant and ultimately leads to a shift in the point of contact of the jaw closing sensor. That can be done by Oversizing of the bearings are taken into account, however accepting higher costs and greater weight.

The invention has for its object a pressing device type mentioned so that the drive more reliable switched off in the intended final pressing position becomes. Another object is to provide a method that supports the above objective.

In a first alternative, the press device itself is concerned Task solved in that the press path in the Storage device is storable or stored and that the control device is a path detection device which cooperates with the storage device in such a way that the drive is switched off when the end of the press path is reached becomes. A second alternative proposes that the pressing device has a position sensor for detection has a reference point on the press path that in the Storage device from the reference point to the end of the press path extending residual press path storable or stored and that the control device is a path detection device has that with the position sensor and the storage device cooperates such that the drive is switched off when the end of the pressing path is reached.

The basic idea of the invention is therefore not the most Pressing adjusting geometry of the press jaw contour to scan a jaw lock sensor, but the entire one Press path or the last part of the press path from a reference point on the pressing device and then save the drive Switch off traversing the saved route. It has shown, that this sets the switch-off point very precisely can be, especially if both for the storage device as well as electrical for the path detection device or electronic components are used. The storability also opens up the possibility to everyone Press tool or any combination of press tool and drive an individually suitable value for the press path or to save the remaining press path after making one Calibration as described below. This will any existing tolerances during manufacture in particular of the press tool switched off.

As for the second alternative, positioners can can be used, such as those resulting from the DE-U-296 02 240 or DE-U-297 03 052, disclosed on May 15, 1997. they are then expediently on the pressing tool itself and advantageously there close to two faces of the press jaws of the Press tool arranged. In contrast to the ones described above However, they are sensors according to the present invention set so that it reaches the final pressing position generate a signal which the path detection device activated for tracing the stored remaining press path. The reference point should be in the second half of the press path and in particular close to the end press position be provided.

Basically, there is the possibility of the storage device to be provided in the area of the control device for the drive. However, this would have the disadvantage that only one Set of pressing tools can be combined with the drive can whose press paths or

Remaining pressing paths are stored on the drive part of the pressing device are. Therefore, it is more advantageous to use the storage device to be arranged for the pressing path or remaining pressing path on the pressing tool itself, care must be taken to ensure that when connecting of the respective pressing tool with the drive part one Connection to the control device via a transmission link will be produced. This way everyone can Press tool with the drive part of a specific pressing device connect.

The path detection device is expediently in the area arranged of the drive, for example as a revolution counter. As far as the entire press path should be saved, should a starting sensor to record the initial position of the Press tool may be provided.

In a further embodiment of the invention it is provided that several pressing paths or remaining pressing paths in the storage device are storable or stored and that a selection device to select the respective press path or residual press path is provided. This training allows for a specific press tool press paths or residual press paths in adaptation to the elastic behavior of the stressed parts of the Pressing device for pressing workpieces with different Save compression resistance. Hereby then also becomes an optimal switch-off point for the drive realized when the pressing tool for pressing Pipe connections made of different materials or different Wall thickness is used.

For the selection of the respective press path or residual press path can be provided a manually operable switch assembly his. In order to provide greater security in this respect, too the selection device an actual value sensor for the Detect a physical quantity, which with correlates the compression resistance, the one at a certain Point of the press travel actual value taken as a criterion used for the selection of the press path or residual press path becomes. The selection of the press path or residual press path is done in this case automatically according to the detected compression resistance at a specific location the press path. As physical quantities, which with the compression resistance correlate, especially come Speed of the drive, the pressing force to be applied, the one to be applied Torque and / or the drive supplied electric current in question.

According to a further feature of the invention it is provided that the control device has a drive control device, via which a calibration process can be carried out in such a way is that the pressing tool with a predetermined force up to an end position can be moved and the pressing path or the remaining press path is determined via the path detection device and then stored in the storage device. there the calibration process should be repeatable and the stored value for the press path or residual press path through the the value determined during the repetition are overwritten. With the help of the drive control device, an automatic Calibration process on the pressing device itself, to submit the connected press tool for the first time or re-calibrate to creep To compensate for changes such as wear.

To store the press path or the remaining press path is a Proposed method in which the press tool with a predetermined force is moved to an end position and the press path or the remaining press path is recorded and then into the Storage device is stored. Every press tool receives an associated press path or residual press path, which causes the drive to switch off when pressed becomes.

The calibration should preferably be done in such a way that the process of the pressing tool several times in succession carried out and thereby the press path or residual press path is detected, such a press path or residual press path being stored which is different from the press path or residual press path, which was recorded immediately before or after, differs less than from the initially determined pressing path or remaining press path. only then should a press path be preferred or remaining press path if the difference to the pressing path or immediately recorded before or after Residual press travel is at least 50% less than that at the beginning determined press path or residual press path. With the above In terms of procedure, signs of settlement appearing at the first or second method of the pressing tool are eliminated become, d. H. only then should the press path or residual press path be saved when there are practically no differences more between two calibration processes.

The method described above can also be modified in such a way that the pressing tool while pressing workpieces with a certain compression resistance up to the end position is moved and that then at least one further value for the press travel or remaining press travel stored which corresponds to another compression resistance. The further value (s) on the Based on the first stored value, because in general the relationships with different compression resistances due to different materials and Wall thicknesses can be calculated for the workpieces to be pressed are. However, there is also the possibility that the or the further value (s) under compression of workpieces of different Compression resistance is determined or become.

It is understood that the press path or the residual press path for the implementation of the invention is not necessarily directly understood must become. It can also correlate physical Sizes are measured and stored, such as the pressing time or remaining pressing time. The latter essentially correspond to a particular pressing device the press path or residual press path and can therefore also be used.

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 illustrating 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 bolts 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 is 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, the 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. The there is also a time interval between two signals a measure of the instantaneous speed of the drive motor 5.

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. A press jaw lever sits on the bearing bolts 32, 33, respectively 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 cheek arms 38, 39. The drive arms 36, 37 have drive surfaces 40, 41, which 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 - on the outside - a press fitting 45 with its radially projecting annular bead 46. The annular bead 46 lies at the level of the press jaws 42, 43 and is intended to Swiveling 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 pressing 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. The in the press tool 3 contained part of the circuit 51 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 one aimed at 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. 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 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. 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 the pressing tool 3.

Via a line 75, the microprocessor 63 becomes specific Specifications submitted. For one, this is the coding of the Press tool 3 via the resistor 50. On the other hand, this is the jaw closing 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 Given signal to the microprocessor 63, in which then this Signal is processed. In a comparative facility 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 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 fault. 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. 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 consistent with 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 further 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 of a blockage because the Speed goes steeply towards zero. For example, 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 If there is more, the speed increases suddenly.

The curve shape according to curve section 89 arises when 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 pipe 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 re-emerging Compression resistance downwards.

For the coding of the pressing 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 kind of Pressing tools 3 can be combined as each pressing tool 3 stores the setpoint curve that is specific to him Has. The difference is the possible combinations 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.

In the memory chip 100 there are also memory locations for the Storage of a residual press path provided. This residual press path is obtained by 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 path to a final press position, in which the drive arms 36, 37 abut one another 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 surrender.

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 driving the remaining press path, 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 its compression resistance distinguish between different materials and / or wall thicknesses. This results from the elastic behavior in particular the press tool 3 different Remaining press paths. 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 is determined at the specific location and the measure of the deviation as a selection criterion is used. Instead, there is also the option of 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 there is still 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 (21)

1. Pressing device (1) for joining workpieces, comprising a pressing tool (3) and a motor drive (5) for operating the pressing tool (3) over a pressing path as well as a control device (26) and with a memory (100), characterised in that the pressing path can be or is stored in the memory (100), and the control device comprises a path detection device (23, 24, 25) which co-operates with the memory (100) in such a manner that the drive (5) is switched off on arriving at the end of the pressing path.
2. Pressing device (1) for joining workpieces, comprising a pressing tool (3) and a motor drive (5) for operating the pressing tool (3) over a pressing path as well as a control device (26) and with a memory (100), characterised in that the pressing device (1) comprises a position sensor (54) for detecting a reference point on the pressing path, and the remaining pressing path which extends from the reference point to the end of the pressing path is storable or stored in the memory (100), and the control device (26) comprises a path detection device (23, 24, 25) which co-operates with the position sensor (54) and the memory (100) in such a manner that the drive (5) is switched off on arriving at the end of the pressing path.
3. Pressing device according to Claim 2, characterised in that the position sensor (54) is positioned on the pressing tool (3).
4. Pressing device according to Claim 3, characterised in that the position sensor (54) is arranged near two end surfaces of the pressure jaws (42, 43) of the pressing tool (3).
5. Pressing device according to one of Claims 2 to 4, characterised in that the reference point lies in the second half of the pressing path.
6. Pressing device according to one of Claims 1 to 5, characterised in that the memory (100) is positioned on the pressing tool (3) which is via a transmission member (51, 52, 53) connected to the control device (26).
7. Pressing device according to one of Claims 1 to 6, characterised in that the path detection device (23, 24, 25) is positioned in the area of the drive (5).
8. Pressing device according to one of Claims 1 to 7, characterised in that the path detection device is designed as a revolution counter (23, 24, 25).
9. Pressing device according to one of Claims 1 to 8, characterised in that a start sensor (47) is provided for detecting the starting position of the pressing tool (3).
10. Pressing device according to one of Claims 1 to 9, characterised in that a plurality of pressing paths or remaining pressing paths are storable or stored in the memory (100), and a selector is provided for selecting a respective pressing path or remaining pressing path.
11. Pressing device according to Claim 10, characterised in that the selector comprises a manually operated switch arrangement (76) for selection of a respective pressing path or remaining pressing path.
12. Pressing device according to Claim 10, characterised in that the selector comprises an actual value sensor (23, 24, 25) for detecting a physical size, which correlates with the moulding resistance, and the actual value picked up at a specified point in the pressing path is utilised as criterion for selection of the pressing path or remaining pressing path.
13. Pressing device according to Claim 12, characterised in that the physical size which correlates with the moulding resistance is/are the revolutions of the drive (5), the pressing load to be applied, the torque to be applied and/or the electric current delivered to the drive (5).
14. Pressing device according to one of Claims 1 to 13, characterised in that the control device (26) comprises a drive control device (64) by means of which the calibration process is performed in such a manner that the pressing tool (3) is movable with at specified load up into an end position whilst the pressing path or the remaining pressing path is detected via the path detection device (23, 24, 25) and then stored in the memory (100).
15. Pressing device according to Claim 14, characterised in that the drive control device (64) is designed in such a manner that the calibration process is repeatable whilst the stored value with the pressing path or the remaining pressing path is exceeded by the value determined during repetition.
16. Process for storing the pressing path or remaining pressing path with a pressing device (1) according to one of Claims 1 to 15, characterised in that the pressing tool (3) is moved with a given load up into an end position whilst the pressing path or the remaining pressing path is detected and then stored in the memory (100).
17. Process according to Claim 16, characterised in that the process of the pressing tool (3) is performed repeatedly and successively whilst the respective pressing path or remaining pressing path is detected, and a pressing path or remaining pressing path is stored which differs less from the pressing path or remaining pressing path which had been detected immediately prior thereto or subsequently than the initially determined pressing path or remaining pressing path.
18. Process according to Claim 17, characterised in that a pressing path or remaining pressing path is stored only when the difference between the directly prior thereto or subsequently detected pressing path or remaining pressing path is at least 50% less than relative to the initially detected pressing path or remaining pressing path.
19. Process according to one of Claims 16 to 18, characterised in that the pressing tool (3) is moved into the end position whilst moulding workpieces (44, 45) at a specified moulding resistance, and at least one additional value for the pressing path or remaining pressing path is then stored which corresponds with another moulding resistance.
20. Process according to Claim 19, characterised in that the additional value(s) is/are calculated on the basis of the first stored value.
21. Process according to Claim 19, characterised in that the additional value(s) is/are detected by moulding workpieces (44, 45) of different moulding resistance.

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