EP1103349B1 - Press tool and method for controling the same - Google Patents

Abstract

The control method has the compression tool (1,5) operated after fitting or replacement of the clamp plates (2) for compression of the coupling element, with detection of the movement path of the hydraulic pistons (12) until a given pressure is reached, for use as a reference value for comparison with the effective path value for each subsequent compression operation, for providing a signal when the difference between the compared values is outside a given tolerance range. An Independent claim for an electrically-operated compression tool is also included

Description

The present invention relates to a method for Control of an electrically operated press tool for pressing coupling elements with a pair of pliers. The invention further relates to a pressing tool device with which the method according to the invention can be carried out.

Press tool devices of the type mentioned at the beginning become Pressing coupling elements, such as press sleeves, press fittings, Pipe sleeves, nested pipe sections and the like. The press tool devices have a Clamping pliers with jaws, which a press room for Form the receptacle of the coupling element to be pressed. The the pressing pressure required for the pressing is carried out by a, in general hydraulic, drive supplied.

After each pressing, it should be checked whether that Coupling element has been pressed in the desired mass or whether the pressing was too strong or too weak is. This check is carried out by a visual inspection.

However, the strength of the pressing is only just outside the tolerance limit, this is by mere visual inspection not visible. It also depends on the reliability of the Worker whether and how carefully he visual inspection performs.

Press tool devices are working tools that have an increased Have an accident risk. There are already several work accidents Occurred where the clamp is uncontrolled was thrown away and the fork-shaped receptacle spread and was deformed.

It has therefore been proposed according to EP-A-0'712'696 Monitoring element to be provided that the connecting bolt in its fully retracted position monitored and over a Switching element is connected to the drive motor.

Even if the clamping pliers in the pressing tool device are correct is not guaranteed to be flawless Pressing the tubular workpieces. Reasons for qualitatively inadequate pressing can be extremely be different. Besides reasons related to the function of the pressing tool device, reasons come in Question that has to do with the insufficient processing. For example, the pliers or their jaws be contaminated, which means that the Clamping pliers is not reached or the dimensioning of the used pipe sleeve or compression sleeve does not correspond to the Dimension that is intended for the corresponding pliers.

For these reasons, according to EP-A-0'858'850 Press tool proposed, in which the adjacent Press pressure is determined and it is determined whether this Press pressure within the predefined tolerance limits lies. From this it is concluded that a complete Closing pliers has been reached. So that Surveillance can be done correctly, however Press tool tool recognize which clamp is used becomes. Such detection of clamp pliers requires an electronic one Exchange of information between the clamping pliers and the pressing tool device, as well as a special electronic logic, by means of which evaluates the information on corresponding signals can be a correct or incorrect pressing Show. Such electronic surveillance can be then easily with further electronic information connect that also the correct actuation and the Show perfect condition of the press tool.

Because these crimping tools are often used in construction contamination of the clamping pliers are hardly to be found avoid. Such contamination often leads to Interruptions in electronic transmission and thus too Misinformation.

In addition, as for example from DE-A-19,631,019, Press tool devices known in which the Final pressing position of the press jaws is monitored. Corresponding the clamping pliers have means which have this final pressing position perceive and to a display device hand off. Here too, an information transfer from the clamp to the press tool. Come in addition, that appropriate electronic means in the jaws have to be integrated in addition to sensitive mechanical elements.

Ultimately, EP-A-0'941'813 also shows a press tool from of interest here. Here it was recognized that both the mechanical as well as the electrical detection of the Clamping pliers is problematic. So here was a contactless one Data transmission from the clamp to the pressing tool made contactless by magnets in the clamp interact with detection sensors on the press tool.

Accordingly, according to the prior art known to date to this day information from the clamp to the Press tool device can be supplied. It is therefore the task of the present invention to provide a method which without electrical or electronic data transmission from the clamp to the pressing tool device practically procured this information themselves.

This object is achieved by a method having the features of patent claim 1.
Further advantageous method steps emerge from the dependent claims 2 to 3 and their meaning is explained in the following description.

The invention provides a pressing tool device, which according to the method according to the invention works.

Figur 1

eine Vorrichtung, bei der die Wegmesssensorik zwischen Rollenhalter und gabelförmiger Aufnahme angeordnet ist und

Figur 2

ein Presswerkzeuggerät, bei dem die Wegmesssensorik in der Kolben/Zylindereinheit integriert ist.

The drawing shows two exemplary embodiments of pressing tool devices that can work according to the method according to the invention. It shows:

Figure 1

a device in which the displacement sensor system is arranged between the roll holder and the fork-shaped receptacle and

Figure 2

a press tool device, in which the displacement sensor system is integrated in the piston / cylinder unit.

The following is for the time being with reference to the drawing Press tool device according to the invention explained and then Procedure described.

In FIG. 1, only the pressing tool device designated by 1 is shown shown, while in Figure 2, the press tool 1 and an inserted clamp 2 shown are. The pressing tool device 1 consists essentially of an electro-hydraulic device that has a pistol shape is. The device has a housing 3 with a handle 4. Am Handle 4 is the trigger switch 5, via which a Pressing process is triggered. The housed in the housing 3 Electromotive drive 6 acts on a gear 7 a hydraulic pump 8, which hydraulic oil from a Presses the storage space into the cylinder and thus moves the piston.

The piston / cylinder unit is designated 10 in total. It comprises the cylinder 11 and the piston movable therein 12. A piston rod 13 engages the piston 12, which passes through a two-part bearing 14 is passed through. On that End 12 opposite piston is on piston rod 13 a roll holder 15 is arranged. The roll holder 15 has the Shape of a yoke in which two rollers 16 are mounted.

The extension of the cylinder housing 11 is in the Milled in the longitudinal direction and thus forms two cheeks 17, which form the fork-shaped receptacle 20. Transversely to the longitudinal direction the cheeks 17 becomes the fork-shaped receptacle 20 of one Safety bolt 18 passes through. Through a monitoring sensor 19 the correct position of the safety bolt 18 supervised. This securing bolt 18 passes through the bearing plates or a connecting strap of the clamp pliers 2. To The clamp pliers 2 must be replaced in each case Safety bolts 18 are removed.

When the trigger switch 5 is actuated, hydraulic oil pressed into the cylinder 11 by the cylinder head 9. Accordingly, the piston 12 is to the right in the drawing postponed. Of course, it moves to the same extent also the piston rod 13 with the attached Roll holder 15 to the right. The rollers 16 come up ramp-like surfaces 25 on the inner surfaces of the two Clamping jaws 21 of the clamping pliers 2 for contact. Swing while doing this the two jaws 21 around the two corresponding Rotary bearings 22 which are arranged in the bearing plates 23. The Bearing plates 23 can themselves be designed so that they are penetrated by the locking pin 18 or it can be appropriate mounting bracket between the two bearing plates 23, which are arranged by the securing bolt 18 is enforced. In the latter version, realize correspondingly larger and wider clamping pliers. In the position of the piston shown in Figure 2 and according to the position of the reel seat or reels the clamp pliers 2 are opened. The rollers 16 move to the right on the ramp-like surfaces 25, so the Jaws 21 on this side of the pivot bearing 22 apart pressed and accordingly on the other side pressed together, the terminal space 26 is reduced, so that the tubular workpiece inside is pressed together becomes.

In the embodiment according to FIG. 1, one of the two cheeks 17 of the fork-shaped receptacle 20 one Recess 27 attached in which a determining the stroke Sensor 28 is arranged. This can be one Magnetic sensor, a magnetoresistive angle sensor, a Act a displacement sensor or a Hall sensor. In the present case is a distance sensor that works with a Magnetic strip 29, which is fastened on the roll holder 15, is in a corresponding operative connection. At the Magnetic stripe is a small plate, which in dense arrangement alternately stripes in plus and Minus poles is divided. When operating the device the roll holder 15 moves and thus the one on it located magnetic strips 29 below the sensor 28, the receives counts corresponding to the changing poles. The number of counting pulses determined is direct proportional to the stroke of the piston 12 or Roll holder 15. Corresponds with the same clamping pliers the constant stroke of the constant Closing movement of the clamp, which results in a constant compression leads.

When using a magnetoresistive angle sensor can this can be accommodated in the cylinder seal through which the piston rod 13 is passed through. The piston rod can then be provided with magnetized areas, wherein the directions of magnetization are different. The magnetoresistive angle sensor detects a vector that corresponds to an absolute position of the piston rod. This preferred embodiment includes a destruction in the Jaw replacement completely out.

The procedure is now such that after the Insertion of the clamping pliers 2 of the release lever 5 is actuated, without, however, one to be pressed into the clamping space 26 Workpiece is inserted. Accordingly, the clamping pliers 2 close completely without hindrance. Is the clamp 2 completely closed, the pressure in the Cylinder space up to a limit that is determined by a built-in pressure relief valve, not shown here is defined. If the appropriate pressure is reached, the valve switches over automatically and the hydraulic oil can from cylinder 11 directly into the storage oil tank flow back. Because usually a torsion spring or Retraction spring is integrated, which pliers into the leads back to the unstressed position Piston 12 pushed back into the starting position. Of course, it is also possible to switch over of the pressure relief valve the direction of rotation of the hydraulic pump reverse the polarity and actively return the oil.

The number determined when the pliers were first closed Signals are supplied to an electronics system, which at 30 im Housing 3 is housed. The electronic circuit contains a data memory, a comparator and possibly further conventional means, on the one hand, to increase the target path value save and below and / or above Enter tolerance ranges and an arithmetic unit, which the actual path values determined with the specified target path value compares and checks whether the actual travel value within the so specified tolerance range.

The particular advantage of the solution according to the invention is before all to be seen in the fact that the determined target path value a Relative value that depends on the type of clamp and even from every single clamp, as such Clamping pliers also show wear, reducing tolerance would practically always get bigger. For systems by absolute values, must accordingly Clamping pliers can either be replaced earlier or readjusted. Every time the clamp is used again due to the above-mentioned empty opening, the real one Closing travel determined and newly recorded as the target travel value. Because neither mechanical scanning elements on the clamp still electronic data transmission elements required the entire system is extremely insensitive in everyday use and all suitable clamp pliers can be used and monitored.

A second embodiment is shown in FIG. The second embodiment differs from that first described embodiment only in relation to the Arrangement of the sensor and the type of sensor. in the Centrally, cylinder head 9 is a hollow cylindrical pin 31 arranged. This pin 31, which is permanently supported in the cylinder head 9 protrudes into the piston 12 and the piston rod 13 into one Blind hole. The corresponding blind hole 32 is so large in diameter that the pin 31 in it can protrude without contact. In the head of the piston 12 an enlarged bore 33 arranged in the magnetic ring 34 is kept fixed. In the hollow pin 31 is a straight or arranged wound wire attached, which at the Movement along the magnetic ring 34 induces a signal, which in turn is connected to the electronic at 30 Circuit is evaluated. Here too is the signal proportional to the stroke of the piston. The evaluation of the Signals occur exactly the same as the one described above Solution. Here too, the clamping pliers determine the Desired stroke and the corresponding tolerances can be found in program the circuit from the manufacturer. The user has no access to setpoint tolerance setting.

In contrast to known systems, this is what is disclosed here Control system for monitoring the clamping pliers does not have regulated the pressure. The hydraulic pressure is subject to considerable Fluctuations that are dependent on external influences, which are hardly considered. In particular, the Viscosity is an essential parameter. The viscosity the hydraulic oil also depends on the temperature. In the solution described here there is only one Pressure relief valve available, which only when a certain security value switches. This value can relatively high above the possible compression pressure lie. In principle, the pressure is so high that the pliers can close securely. This is accordingly Value completely uncritical for the actual pressing. This is another significant advantage of solution according to the invention.

To avoid misinformation, the electronic Circuit in the press tool device so that the Elimination of the tension on the press tool device the saved Setpoint value disappears. This is to ensure that if the clamp is replaced, while the device is switched off, when switching on again an incorrect stored value is not assumed. This would not be a tragedy, because then the entered one Target value is either fallen below, whereupon the device perceives this pressure as a new empty pressure and so save the determined value as the new setpoint value and this process also optically and / or acoustically shows. However, it is certainly desirable that at Resumption of work after changing the clamp a new empty pressing or full pressing takes place and this Empty pressure is determined as a reference.

In principle, changing the Clamping pliers are monitored and accordingly when they are removed the stored setpoint value is deleted become. The easiest way to do this is to: the removal or reinstallation of the safety bolt 18 used as information. This is complete possible without any problems because the sensor 19 is present anyway is who monitors the safety bolt. Corresponding the information from the sensor 19 only has to be logical with the Information from the sensor 28 are coupled.

Claims (8)

1. A method for controlling an electrically operated pressing tool apparatus (1) for pressing coupling elements with a clamping pincer (2), wherein the pressing tool apparatus moves a hydraulically actuatable piston (12) until reaching a predetermined pressure and with this closes the clamping pincer (2), characterised in that with the insertion or exchange of the clamping pincer (2) the stored nominal displacement value is deleted and thereafter the pressing tool apparatus (1,5) is actuated with or without carrying out a clamping, wherein the displacement which the piston (12) covers up to reaching a predetermined safety value of the pressure which lies above the required pressing pressure is registered and as a nominal displacement value up to settable tolerances is compared to each effective displacement value of every subsequent pressing procedure. wherein deviations from the nominal displacement value activate a signal.
2. A method according to claim 1, characterised in that the stored nominal value displacement is deleted with the cessation of the voltage at the pressing tool apparatus (1).
3. A method according to claim 2, characterised in that on falling short of the stored nominal displacement value this lower value is recognised as an erroneous pressing and is optically and/or acoustically displayed.
4. An electrically operated pressing tool apparatus (1) for carrying out a method according to one of the claims 1 to 3 with an electrically operated hydraulic pump (8) which acts on a hydraulic piston-cylinder unit (10) which is in active connection with a roller holder (15) whose rollers (16) roll onto the clamping jaws (21) of a clamping pincer (2) and with this move these relative to one another, and that the clamping pincer (2) is exchangeable and is held in a fork-like receiver with a securing bolt, wherein the apparatus comprises a logic circuit as well as a sensor which determines the stroke displacement of the piston and is in data-transmitting connection with the logic circuit, characterised in that sensor determining the stroke displacement is a magnet sensor, magnet field sensor, path or Hall sensor or a rotation sensor which after the nominal value has been deleted on exchange of the clamping pincer determines the stroke displacement of a first pressing and delivers this to the logic circuit as a new nominal value.
5. A pressing tool apparatus according to claim 4, characterised in that the sensor determining the stroke displacement is arranged in the fork-like receiver and on a part connected to the piston there is arranged a magnet strip.
6. A pressing tool apparatus according to claim 4, characterised in that the sensor determining the stroke displacement or a magnet lies in an open hollow-cylindrical, fixedly arranged pin which is arranged projecting into the piston and is surrounded by a magnet or sensor fixedly fastened on the piston or on the piston rod.
7. A pressing tool apparatus according to claim 6, characterised in that the hydraulic pressing pressure bears on the outside on the hollow-cylindrical pin.
8. A pressing tool apparatus according to claim 4, characterised in that the sensor determining the stroke displacement is a magneto-resistive sensor which is arranged in the region of the piston rod mounting and detects the magnet field angle of magnetic fields arranged on the piston rod and delivers these to the logic circuit.

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