EP3151987B1 - Radial press - Google Patents

Description

The present invention relates to a radial press with a frame structure, a pressing tool, a drive unit and a press control, wherein the pressing tool comprises a plurality of evenly concentric about a press axis around arranged, pressing surfaces having pressing bodies which under appropriate action on the drive unit synchronously selectively in the direction of Press axis or are movable away from it.

Radial presses of the type mentioned above are used for various applications, for example for connecting fittings with hose sections in the production of ready-to-install hydraulic hose lines. They are known in various constructions and designs, for example as so-called "yoke presses" (cf. DE 4135465 A1 . DE 19912976 A1 and DE 19817882 B4 ), "Hollow piston press" (cf., for example DE 10149924 A1 ) or in other construction (see eg DE 2844475 A1 . DE 3611253 A1 . DE 10047025 C2 and DE 3331721 A1 ).

Generic radial presses have proven themselves in practice. When used properly, for example, long-lasting, very high requirements sufficient connections between two components (eg hose section and connection fitting) can be produced. Regardless of the present invention has the object to further improve radial presses of the type specified in terms of their handling, and In particular, to the extent that high-quality results are even less dependent than ever on the experience and / or detailed training of the respective operator or, in other words, the risk of producing inferior results is reduced by less experienced or trained operating personnel.

This object is achieved according to the present invention by arranged at a radial press of the generic type on the pressing tool in the direction of the press axis spaced positions at least two associated with the press control comparator signal transmitting connected transducers, wherein exceeding a stored in the press control tolerance the triggering of a signal output unit is triggered by the comparison value generated in the comparator of the measured values provided by the transducers. The radial press according to the invention is thus characterized, in other words, by the fact that at least two transducers are provided on its pressing tool, in an arrangement staggered in the direction of the pressing axis. These two transducers are signal-transmitting connected to the press control, namely with a comparator associated therewith, in which during the execution of the pressing or at least at the end of the provided by the two transducers measured values or possibly measured value curves (continuous or intermittent) are compared. If the comparison value determined in this case is - depending on the specific design of the sensor For example, in the difference between the measured values provided by the pickups or their relationship to one another, outside a tolerance range stored in the press control, the output of a signal which gives the operator a result deviating from the target range or an unscheduled course of the pressing occurs signaled. In this way, in particular various errors caused by the operator, which can be reflected in an inferior version of the pressure, recognized early and a corrector can be made. This applies in particular to an incorrect positioning of the workpiece within the radial press, ie offset more or less in the direction of the press axis to the ideal position. In this way, the present invention makes use of the insight that even a rather small offset of the workpiece - in the direction of the press axis - relative to its ideal position leads to internal (asymmetric or off-center) force relationships, which cause such a deformation of the radial press deviates from its desired shape deviating result of the pressing, for example, by the workpiece is slightly conical at the end of the pressing instead of cylindrical. Such a situation can not be detected with conventional press controls even in the case of monitoring the press force during the press cycle; because the pressing force as such typically moves within the given bandwidth, but is introduced over the axial extent of the workpiece to varying degrees in the latter, because by the said offset caused deformation of the radial press to a - more or less pronounced - oblique position of the pressing surfaces relative to the press axis leads.

When the radial press according to the invention is used, in the case of such positioning of the workpiece within the radial press, deviating from the ideal position, the ratio of the measured values provided by the two transducers shifts out of the tolerance range stored in the press control. This is signaled to the operator, possibly with simultaneous automatic termination of the pressing process. If such a detection takes place not only or not at the end of the pressing process, but rather (continuously or at least intermittently) over the pressing process, the latter can be broken off so early that a correction of the pressure is possible, ie reject does not arise , First and foremost, in the practice of the present invention, gross operating errors or significant disturbances can be detected immediately, for example the presence of foreign bodies in the region of the workpiece, the processing of defective (eg broken) workpieces or the like, with a workpiece fracture occurring during the pressing process, for example in a distinct manner Discontinuity of the readings provided by the transducers. The detection of incorrect operations is also in terms of the life of the radial press of great advantage, for example, by the pressing process is stopped immediately, if there is an indication by a corresponding reference value that one with a The connection fitting to be connected to the hose has been inserted into the radial press up to the union nut or there is a foreign object in the tool.

Even if less experienced or less trained personnel is used to operate the radial press, in the case of using a radial press according to the invention the risk of producing inferior workpieces by the radial pressure is much lower than in the case of using known generic radial presses according to the prior art ,

The measured values provided by the measuring sensors can also be used in a preferred manner for an individual workpiece-related modification of the press profile stored in the press control. In this sense, for example, it is possible to modify the pressing speed as a function of the measured values of the measuring sensors and in this way to optimize them specifically with regard to the individual workpiece to be pressed. Tolerances within the tolerance with respect to the dimensions and / or the material of the workpiece can thus be taken into account when carrying out the individual pressing.

Furthermore, when using the radial press according to the invention by way of a comparison of the forming of the workpiece causing forces for which - in a suitable design, the transducers - the measured values provided by the transducers are an indicator, and the energy consumption of the radial press a Efficiency analysis possible. Again, this is a measure that allows an optimization of the pressing process - in terms of its energy efficiency.

A further positive effect of the present invention is the possibility of saving material in the production of the workpiece (with the same performance). Because by optimizing the forming of the workpiece in the radial press according to the invention (see above), the workpiece needs to have fewer safety margins than this - for example to ensure a secure and reliable connection of a connection fitting with a piece of tubing - when machining corresponding workpieces on conventional radial presses is required.

However, the positive effects of the present invention are not limited solely to the quality of the pressed workpiece. Rather, the monitoring and analysis or evaluation of the measured values provided by the transducers permits conclusions to be drawn about the state of the radial press, for example the wear of wearing parts. This makes it possible to match the maintenance intervals and the replacement of wearing parts better to the individual needs of the individual machine. A precautionary early replacement of wearing parts is not required in this case, which is a significant economic aspect. At the same time, security can also be increased; because by the monitoring and analysis or evaluation of the provided by the transducers Measurements can - in addition to the resulting anomalies of the measurements - even damage (eg cracks in pressing or other parts of the pressing tool), which could possibly even consequential damage with a risk to the operating personnel, immediately recognize. The same applies to the detection of fatigue of machine components as well as conceivable manipulations of the radial press. For the purpose of optimizing the processes and the quality assurance, the measured values determined are preferably stored over a longer period, archived (possibly compressed) and evaluated, with a transmission (online or on data carrier) to the machine manufacturer - for a statistical, on several radial presses related evaluation - comes into consideration.

Furthermore, in the case of a suitable design of the at least two transducers, the measured values provided by them can be used for a significantly more accurate determination of the pressing force compared to the presence of only one pressing force sensor.

Especially meaningful findings about the state of the radial press and of the pressed workpiece arise when the measured values provided by the transducers are set in relation to process parameters characteristic of the pressing process, such as the pressure in a hydraulic cylinder associated with the drive unit, the time within a pressing cycle 'and / or the path of the drive for the pressing tool. By comparing the determined values with setpoints, as they are characteristic of the pressing process to be performed, not only can irregular operating conditions be noted, such as the pressing of a wrong workpiece, the use of a wrong pressing tool, the absence of individual compacts or the like. Evaluations are also useful in regular press runs, for example, by determining the ideal duration of press holding at the end of the press, depending on how the readings provided by the transducers change over time. Thus, in the interests of high efficiency, ie the shortest possible cycle times, in conventional radial presses, as a precaution, long measured holding times can be shortened. In this sense, the radial press can be opened as soon as the change in the measured values over time (measured value gradient) falls below a certain value.

The course of the measured values when opening the radial press, on the other hand, provides immediate information on the springback of the workpiece. Thus, it can already be determined at an early stage, ie when the radial press is not yet fully open, that a certain repressing is still required, so that the (spring-loaded) workpiece complies with its specified dimension after opening the radial press. Comparable conclusions on the subsequent springback of the workpiece can be drawn from those measured values, which determine the at least two transducers when the desired dimension of the workpiece is reached for the first time, so that the degree of a required overpressing can already be determined taking into account these measured values.

It has already been indicated above that, in addition to the (in particular optical and / or acoustic) signal output unit, by means of which the operator is made aware of the unscheduled course of the pressing, it may be provided that - by appropriate influence on the drive unit - the pressing process automatically interrupted or aborted. It is advantageous if the signal output unit has a comparison value display and / or a correction value display, which allows the operator to determine the extent of a possible incorrect positioning of the workpiece or the correction required accordingly. In the press control itself, the value for a positional correction of the workpiece can be calculated from the deviation of the comparison value of the two measured values provided by the transducers from the ideal value stored in the press control for the relevant pressing process, and, for example, a stop for the workpiece accordingly shifted. The same applies to the visual display of a corrected position of the workpiece, for example by means of a laser marking.

According to another preferred embodiment of the invention it is provided that three in the direction of the pressing axis spaced-apart transducers are provided. The third transducer may in particular provide a reference value, for which purpose it ideally more or less centrally between the other two transducers or in the - on the press axis vertical plane of symmetry of the radial press is arranged. The simultaneous consideration of the signals of all three transducers provides additional information from which in particular workpiece-specific anomalies (eg punctual damage to the workpiece) can be concluded.

The present invention can be realized with excellent results even in such widely used radial presses whose compacts are constructed in several parts, in particular by - two-piece structure - each radially outside a base jaw and radially inside a removable jaw or - built in three parts - a base jaw, a Include intermediate jaw and a removable, the pressing surface having pressing jaw. Particularly meaningful results result in this case when the transducers are arranged on at least one pressing jaw, and preferably in the region of the two opposite in the direction of the pressing axis opposite ends. Under structural and other practical aspects, however, the arrangement of at least two sensors on at least one base jaw is particularly favorable. Although the signal strength of the signal provided by the respective transducer is typically lower in this arrangement of the transducer than in the case of the arrangement of the transducers on the pressing jaw directly adjacent to the workpiece, which would rather speak for the arrangement of the transducers on the latter; However, the signal is still sufficient when properly designed the arranged on a base jaw transducer strong that a reliable evaluation in the sense of the present invention can be done. And the disadvantage of a lower signal strength is more than offset by pronounced advantages in terms of the reproducibility of the measurement results and also the handling of the radial press during operation. Among the latter aspect is that in the arrangement of the transducers on at least one base jaw the pressing jaw change, as it is required for conversion of the radial press from one pressing task to another, is not hindered. Also, when the transducers are arranged on at least one base jaw, there are significant advantages in terms of cost; because in this case, reliable and cost-effective transducers with a wired signal transmission can be used, and it is not the equipment of all prepared for the different pressing tasks set of press jaws with transducers required. If, on the other hand, it is desirable in individual cases to arrange the transducers on the pressing jaws, the latter are particularly preferably prepared for wireless signal transmission in order to avoid the expense associated with the connection of the transducers to the press control during each conversion of the radial press.

In such radial presses (typically "yoke presses"), in which one of the base jaws - is arranged in a fixed position relative to the frame structure, at least two transducers are preferably arranged at least on that stationary base jaw. This proves in terms of to a simple construction of the radial press according to the invention with simultaneous high reliability as particularly favorable. In that regard, as far as the signal quality is concerned, it is particularly important to ensure that there are no disturbing influences, as is the case in the case of non-stationary, ie, base surfaces which are slidably supported on control surfaces.

In the context of the present invention, transducers of different designs can be used to detect the load states leading to unscheduled results discussed above. Particularly favorable results can be achieved with comparatively low cost with transducers, which are designed as Verformungsaufnehmer. In particular, strain gauges should be mentioned here as particularly preferred embodiments. Excellent evaluable signals provide full-bridge strain gauges, which can be attached in particular to the end faces of the compacts (in particular the base jaws). Instead of indirectly determining the stress states via the deformation caused thereby, as detected by strain transducers such as strain gauges, however, the stress states (for example in the at least one base jaw) can also be detected directly and directly using corresponding transducers.

The sampling rates of the transducers depend on the workpiece to be pressed. While for typical applications (eg pressing a connection fitting with a hydraulic hose) sampling rates preferably in the range between 5ms and 10ms (corresponding to a frequency between 100Hz and 200Hz), are for sensitive applications of the radial press according to the invention (eg when pressing or ceramic components such as insulators) sampling rates preferably lower, eg in the range between 1ms and 10ms (corresponding to a frequency between 100Hz and 1kHz) or even lower.

The tolerance range stored in the press control and used in the evaluation of the measured values provided by the transducers is particularly preferably adjustable by means of an input unit. This takes into account the fact that, for different pressing tasks, different relationships of the measured values provided by the individual measuring sensors relative to one another can prove to be ideal, favorable or tolerable. In particular, the relationship that ideally holds the measurements provided by the transducers depends on which is the ideal position of the workpiece within the crimping tool.

Alternatively or additionally, the press control may in particular also include an adaptation circuit for the tolerance range, which takes into account as an input signal the geometric position of the pressing surfaces relative to the position of the pickup. In this embodiment of the present invention is taken into account that (in multi-part compacts), the axial length of the pressing jaws - especially those for small workpiece diameter - Is often substantially less than the axial length of the base jaws, on which ideally the end of the transducers are mounted (see above). In this case, the pressing jaws are typically not positioned centrally on the base jaws, but rather in such a way that pressing jaws and base jaws are flush on the side facing the operator. This in turn leads to the fact that the pressing surfaces are typically offset relative to the center of the base jaws. The larger the offset, the more pronounced the ideal values of the pressure differ from the measured values provided by the transducers.

It was possible to determine that very good results (in particular in terms of high reproducibility) can already be achieved in the case of the use of two transducers assigned to a particular compact. However, this does not exclude, in the interests of redundancy or the possibility of additional plausibility checks distributed over the circumference (in particular on multiple compacts) to provide transducer assemblies each having at least two transducers, wherein in the press control averaging on the one hand the measured values of those transducers, on the Operator-facing side of the radial press are arranged, and on the other hand, the measured values of those transducers, which are arranged on the side facing away from the operator of the radial press, can take place. Within the comparator, a comparison of the one and the other average takes place with one another, in order to determine a possible unplanned load situation in the sense of the explanations set out above.

The radial press according to the invention can furthermore, according to yet another preferred development, have a temperature sensor whose signal is fed to the machine control. As a result, temperature-related influences, such as the lubricating behavior of lubricants that depends on the operating temperature, can be taken into account and compensated. In this sense, in the machine control, preferably for each predetermined pressing operation, a plurality of temperature-dependent characteristic maps concerning the ideal comparison value of the measured values and the permissible tolerance are stored. In this way, even better workpiece qualities can be achieved.

Fig. 1

ausschnittsweise in Draufsicht die dem Bediener zugewandte Stirnseite des Presswerkzeugs der Radialpresse mit erfindungsgemäßer Ausstattung und

Fig. 2

ausschnittsweise in perspektivischer Ansicht die dem Bediener abgewandte Stirnseite des Presswerkzeugs der Radialpresse.

In the following, the present invention will be described with reference to a preferred embodiment illustrated in the drawing, in which a construction of the radial press designed as a yoke press substantially corresponds to the (referred to so far) DE 4135465 A1 underlying, explained in more detail. It shows

Fig. 1

Sectionally in plan view of the operator facing end face of the pressing tool of the radial press with inventive equipment and

Fig. 2

fragmentary perspective view of the operator facing away from the end face of the pressing tool of the radial press.

The radial press underlying the present embodiment largely corresponds to that in the DE 4135465 A1 described and explained construction, as it is also widely used in practice. To avoid repetition, reference is therefore made in full to the cited publication.

Recognizable are in the in Fig. 1 shown section of the front plan view of the pressing tool the (stationary) lower yoke 1, five compacts 2, arranged between the press springs 3, the two inserted into the lower yoke 1 sliding plates 4 and attached to the "45 ° -Presskörpern" sliding plates. 5 Other than this in the DE 4135465 A1 illustrated, touched after Fig. 1 the lower, stationary to Unterjoch 1 arranged compact 2.1 the lower yoke not directly, but is based exclusively on the sliding plates 4 from. And continue to illustrate the Fig. 1 and 2 the three-part structure of the compacts 2 each consist of a base jaw 6, a removable attached to this intermediate jaw 7 and removably attached to the latter, the pressing surface 8 having the pressing jaw 9, as is typical when using compacts with large radial extent for pressing tasks with relatively small diameter , If the radial press is converted to the machining of workpieces with a comparatively large diameter, pressing jaws 9 are used, which are mounted directly on the base jaws 6, so that in this case the pressing bodies 2 are in two parts.

Fig. 2 branches a typical situation of the individual parts of three-part compacts 2 to each other, as far as the axial extent. Namely, the intermediate jaw 7 is significantly shorter than the base jaw 6, and the pressing jaw 9 is in turn significantly shorter than the intermediate jaw 7. Thus, in a typical application, for example, 70mm long pressing jaws on 118mm long base jaws are used, wherein the pressing jaws 9, the Intermediate jaws 7 and the base jaws 6 on the side facing the operator ( Fig. 1 ) close almost flush.

At the bottom, stationary compact 2.1, namely its base jaw 6.1 end of the two opposite end faces 10 and 11 transducers 12 in the form of full-bridge strain gauges 13 and 14 are attached. These are signal-transmitting via signal cable 15 to the press control, namely connected to a comparator associated therewith.

Claims (14)

1. A radial press comprising a frame structure, a pressing tool, a drive unit and a press control, wherein the pressing tool comprises a plurality of pressing elements (2) comprising pressing surfaces (8), which pressing elements are arranged uniformly concentrically around a press axis and which can be moved synchronously, optionally in the direction towards the press axis (A) or away from the latter, by corresponding actuation of the drive unit, characterised in that at least two measured value recorders (12), connected in a signal-transmitting manner to a comparator assigned to the press control, are arranged on the pressing tool at positions which are spaced apart from one another in the direction of the press axis (A), wherein actuation of a signal output unit is triggered if a tolerance range stored in the press control is exceeded by the comparison value, generated in the comparator, of the measured values provided by the measured value recorders (12).
2. The radial press according to claim 1, characterised in that the press control automatically acts on the drive unit if the tolerance range is exceeded by the comparison value of the signals provided by the measured value recorders (12).
3. The radial press according to claim 1 or 2, characterised in that three measured value recorders (12) arranged spaced apart from one another in the direction of the press axis (A) are provided.
4. The radial press according to any one of claims 1 to 3, characterised in that the pressing elements (2) each comprise base jaws (6) and removable pressing jaws (9) comprising the pressing surfaces (8).
5. The radial press according to claim 4, characterised in that removable intermediate jaws (7) are arranged in each case between the base jaws (6) and the pressing jaws (9).
6. The radial press according to claim 4 or 5, characterised in that measured value recorders (12) are arranged on at least one base jaw (6) in the region of its two ends lying opposite one another in the direction of the press axis (A).
7. The radial press according to claim 6, characterised in that the measured value recorders (12) are arranged on the end faces (10, 11) of at least one base jaw (6) .
8. The radial press according to any one of claims 4 to 7, characterised in that the measured value recorders (12) are arranged on a fixed base jaw (6).
9. The radial press according to claim 4 or 5, characterised in that the measured value recorders (12) are arranged on at least one pressing jaw (9) in the region of its two ends lying opposite one another in the direction of the press axis (A), which measured value recorders communicate wireless in a signal-transmitting manner with the press control.
10. The radial press according to any one of claims 1 to 9, characterised in that the measured value recorders (12) are constituted as deformation recorders, in particular as full-bridge strain gauges (13).
11. The radial press according to any one of claims 1 to 10, characterised in that the signal output unit comprises a comparison value display.
12. The radial press according to any one of claims 1 to 11, characterised in that the tolerance range can be set by means of an input unit.
13. The radial press according to any one of claims 1 to 12, characterised in that the press control comprises an adaption circuit for the tolerance range, which adaptation circuit takes the geometrical position of the pressing surfaces (8) relative to the position of the measured value recorders (12) into consideration as an input signal.
14. The radial press according to any one of claims 1 to 13, characterised in that it comprises a plurality of recorder arrangements arranged distributed around the press axis (A) and each having at least two measured value recorders (12), wherein the formation of an average value takes place in the press control.

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