Method for the pressing of a press fitting, and pressing tool for this purpose

p0001The invention relates to a method for pressing a pressfitting with a pipe inserted into the pressfitting by means of a pressing tool, wherein the pressfitting has a peripheral bead in which an O-sealing ring is inserted, the pipe terminating within the pressfitting and in the region of the bead A further pressing is carried out at a distance from the bead on the plug-in side of the press fitting which leads to a tapering conicality of pressfitting and tube, which is prevented from being pulled off in the same direction, and the bead is pressed in the course of pressing by pressing radially outwards and outwards The pressing of the pressed combination of the pressfitting and the tube is only carried out on the press-fitting end on the tube without a pressurization of the fitting section extending behind the bead as viewed in the insertion direction of the tube from the <patcit id="pcit0001" dnum="US5484174A"><text>US 5,484,174 A</text></patcit> In which known method, but without formation of a conical section, a latching is performed and no means for axial alignment with respect to an end face of the press fitting are provided.

p0002In such processes, the necessary tightness of the compression of the pipe and the pressfitting is achieved by the first pressing in the region of the bead, in which the O sealing ring which is present in the bead is pressed by the pressing tool in the region of the bead by means of the pressing tool while the sealing ring is deformed Which is covered by the sealing ring, of the tube. The deformation of the sealing ring is accompanied by a deformation of the region surrounding the sealing ring, both of the press fitting and generally of the pipe. The second pressing, which is carried out at the same time as the first pressing, leads to a deflection of the pressfitting and the pipe in such a way that a conicity of the combination of the pressfitting and the pipe expands opposite the pulling-off direction so that a pull-off inhibition is achieved after the pressing operation .

p0003In the case of a <patcit id="pcit0002" dnum="WO9857086A1"><text>WO98 / 57086A1</text></patcit> , The sealing ring deformation is achieved by the first pressing in the region of the bead, with a corresponding increase in the tightness and at the same time the triggering of the triggering.

p0004In the case of a <patcit id="pcit0003" dnum="US6581983B1"><text>US 6,581,983 B1</text></patcit> The pressing is carried out in the bead region and on both sides of the bead. From the<patcit id="pcit0004" dnum="US4850621A"><text>U.S. Patent 4,850,621</text></patcit> A simple plug-in connection of pipes is known. With one from the<patcit id="pcit0005" dnum="DE29521410U1"><text>DE-U1-29521410</text></patcit> It is possible to achieve a uniformly running conicity of the pressfitting and tube during a pressing operation.

p0005Starting from the initially mentioned prior art, the invention is concerned with the problem of specifying a method for pressing a pressfitting with a tube inserted into the pressfitting by means of a pressing tool which can be carried out in a favorable manner even under difficult installation conditions and results in reliable pressing.

p0006This object is achieved in the subject matter of claim 1. In particular, in the course of the pressing process, this is uniformly widened by pressing radially outward and extending from an apex of the bead, and an abutment web is brought into abutment against an end face of the press fitting for axial alignment on the end of the pressing tool facing the cone pressing section.

p0007The influence of the bead receiving the sealing ring is directly influenced by the radially outer portion during the pressing operation, which results in an axial widening of the inner wall of the sealing ring, which is defined by the bead, with a corresponding radial reduction in the bead diameter. Correspondingly, the inserted sealing ring is correspondingly deformed to form an enlarged pressure-bearing sealing surface. A pressurization of the fitting section extending behind the bead in the insertion direction of the tube, which can be problematic in difficult areas, for example, is not present. Thus, the method according to the invention proves to be of advantage here, since only the bead has to be directly influenced and, in addition, a secure alignment is achieved by contacting the abutment edge on an end face of the press fitting. Moreover, the proposed method also visually shows a correct pressing, in particular a pressurization applied to the inserted seal, this being the axial expansion of the bead, which can be seen from the outside. The radial influence on the bead in the course of the pressing operation can lead, for example, to an axial broadening of the bead by 1.5 to 4 times, more preferably by about 2 times the original axial dimension of the bead.

p0008The bead is flattened in the course of the pressing by applying pressure to the radially outer surface. Thus, for example, the bead is formed in a form-fitting manner before the pressing process for receiving a sealing ring which is circular in cross-section. After the pressing operation and, in this case, from the radially outward acting on the bead, the latter is deformed in such a way that the bead radius adapted to the circular diameter of the sealing ring is enlarged in particular with respect to a transverse section through the bead in the apex region in such a way that a flattenable flattening can be observed on the outside And the bead ring from the original preferred circular disk cross-sectional shape deforms into an oval cross-section, the adjacent sealing surface being enlarged in particular towards the inserted tube. The flattening of the bead by radial loading from the outside leads to the axial widening of the bead, which can be uniformly reached from the apex of the bead on both sides.

p0009The radial loading of the bead from the outside can take place partially on a plurality of areas which are arranged uniformly one behind the other in the circumferential direction. An embodiment in which the bead is acted upon by a cylinder section on the pressing tool is preferably used for circumferentially uniform radial influencing of the bead from the outside, so that correspondingly uniform, continuous axial broadening or radial flattening of the bead is achieved correspondingly even after the pressing operation has been carried out.

p0010The rohreinsteckseitige more pressing to create the trigger inhibition is in a preferred Substituted Structuring the subject invention in the range of at least 1.5 times the height dimension or more of the unpressed bead corresponding distance towards performed from the bead towards the rohreinsteckseitige fitting end, further wherein the height Of the non-compressed bead is defined according to the invention by the radial distance dimension between the non-pressed fitting inner wall and the radially outer vertex of the non-pressed bead. The axial distance of the further pressing to the bead can be 2 times, 3 to 10 times the height dimension of the bead, moreover, for example, 3 times or 4 times or each intermediate dimension, in particular in the tenth range, for example 2.1 or 3.7 times the height. This axial distance between the pressing regions can also be provided in the axial direction with a distance corresponding to 5 to 20 times the thickness of the material of the press fitting, for example with a 6 to 7 times, so also, for example, a 5.7 Or 6.3 times the thickness of the material thickness, the axial distance between the pressing regions being in each case related to an axial center of each pressing region.

p0011A stabilization of the pressing tool relative to the longitudinal axis of the pipe is carried out on the end of the bead facing away from the pipe-engaging end of the press-fit by means of a gauge section on the pressing tool. This gauging section can also be used to prevent an axial widening of the bead in the side facing away from the pipe-engaging end. Correspondingly, the gauging section, with a corresponding arrangement, provides a bead support which is rearward with respect to the tube insertion end. In addition, the fitting to be pressed is thereby fixed in the axial direction during the pressing operation. A movement of the same is counteracted, so that the pressing geometries associated with the respective zones can act in a targeted manner.

p0012Formation of the trigger is carried out in a further development of the subject matter according to the invention, which in a preferred embodiment provides for maintaining the cylindrical fitting section and, in addition, also the raw section covered in this region between the zone of the bead pressing and the zone of the plug- A cross-section which sets in this circumferential range deviates from a circular shape.

p0013In addition to the bead portion provided on the bead side, a further axial alignment of the pressing tool is carried out with the aid of an abutment member abutting an end face of the press fitting. This abutment web thus acts against the free end face of the pipe fitting-side fitting end. As a result of this embodiment, the pressfitting is fixed in the axial direction between the abutment web abutting against the free end edge and the gauge section adjoining the bead when viewed from this free end. For a further exact alignment of the pressing tool with the pressfitting and the pushed-in tube to be pressed, a teaching-like embracing of the tube is carried out on the side of the abutment web facing the bead. The teaching further provided for this purpose at least scans the outer wall of the tube over a partial circumference of the tube.

p0014Furthermore, a radially prestressed press section can be provided on the tube-side of the bead. This pressing section can be formed like a pin-like, for example in the form of a spring-loaded pushbutton, in the cooperation area with the fitting; Alternatively, also in the manner of a gauge, extending in the circumferential direction of the fitting in a circular-section-like manner. It is essential that this press section is positioned in the press jaul, that is to say in the region which directly acts on the fitting during the pressing process. Such a prestressed press section serves, in particular, as a centering aid when the pressing tool is placed on a fitting to be pressed. In order not to be damaged during pressing, the prestressed pressing section deviates in the course of pressing and upon reaching or exceeding the prestressing force, for fitting into the remaining pressing geometry. Only in such an end position does the latter press, in particular, press into the fitting, which is prestressed radially radially and accordingly correspondingly radially outwards, to the fitting, either as an active component of the pressing geometry or as a passive element, for example to form an axially acting support back. Thus, for example, the prestressed pressing section acts in the area of ​​the calibration pressing, for example in a transition area between a calibration pressing section and a bead pressing section. The pretension acting on the pressing section is applied, for example, by a spring, further for example by a cylinder pressure spring. Other elastic elements are also conceivable. It is also provided that, prior to a radial deflection of the prestressed press section, there is no plastic deformation of the fitting, in particular in the immediate contact area with respect to this press section. The pretensioning force (spring force) is correspondingly selected to be such that, by means of this, the pressure portion is released radially radially in the pressed uninfluenced position. Again, the pretensioning force is less than the pressing force, so that the pressing section, due to the pressing and the associated plastic deformation of the adjacent regions of the fitting, is avoided radially outwards.

p0015The invention also relates to a pressing tool for pressing press fixtures on pipes, wherein the pressing tool has at least two pressing jaws with a first pressing geometry adapted to a bead formed in the press fitting for forming a bead pressing section and a second pressing geometry which is axially spaced therefrom to form a cone pressing section The first pressing geometry having a larger diameter has a cylindrical configuration such that a bead is left at least in one directional space for axial broadening, the second pressing geometry being formed only on one side of the first pressing geometry and for pulling out a pressed combination of pressfitting and And a calibrating pressing portion provided between the bead pressing portion and the conical pressing portion is provided between the bead pressing portion and the conical pressing portion, wherein the conical pressing portion leaves a reduced radial interior space against the bead pressing portion, and the calibrating pressing portion leaves a radial interior whose diameter Dimensionally between that of the cone-pressing portion and the bead-pressing portion.

p0016Pressing tools of the type in question are known, for example for the production of pipe press connections according to the initially mentioned <patcit id="pcit0006" dnum="WO9857086A1"><text>WO 98/57086 A1</text></patcit>. Also in this connection is to the<patcit id="pcit0007" dnum="US5484174A"><text>US-A-5484174</text></patcit> . From the<patcit id="pcit0008" dnum="DE29521410U1"><text>DE 295 21410 U1</text></patcit> Such a pressing tool is known in which the bead pressing section is designed to be rounded to form a pressing bead of a press fitting, wherein a cone pressing section is also provided, but an orientation of the pressing tool relative to the fitting can not be reliably achieved

p0017The object of claim 6 is proposed in order to make a pressing tool of the type under discussion in a favorable manner, particularly in terms of handling technology, with further functional safety of the press connection to be produced.

p0018The second pressing geometry is designed only on one side of the first pressing geometry and serves to secure the pull-out of a pressed combination of pressfitting and pipe. In the course of the pressing process, a deformation of the bead is achieved in such a way that the latter widens in the axial direction with reduction of the radial dimension, this further with corresponding deformation of the O-seal ring received on the bead-side; sealing once again by a correspondingly enlarged contact surface in the axial direction Against the outer wall of the pipe. The deformation of the bead is here effected by a direct radial loading from the outside via the corresponding pressing geometry of the tool. This geometry can be shaped in such a way that the broadening of the bead with respect to a cross-section through the bead adjusts on both sides of an apex zone of the bead, for example uniformly on both sides. In a preferred embodiment, the pressing geometry is formed in such a way that the axial widening takes place predominantly only in one direction, so further preferably in the direction of the pipe-engaging end of the press fitting. The compression in the region of the bead and the accompanying impingement of the inserted sealing ring into the sealing position is visible from outside due to the proposed pressing geometry after the pressing process by the altered external shape of the bead. Correspondingly, a control of a properly performed pressing process, in particular of a correct pressing in the sealing zone, is visually achieved. A favorable alignment of the tool can be achieved by the contact element, which is formed on the end of the pressing tool facing the conical-pressing section, for abutment against an end face of a press fitting.

p0019In a further development, a radially prestressed press section is provided in the pressing geometry which, in the course of pressing and achieving the prestressing force, radially eases to fit into the remaining pressing geometry, which press section can be designed in the manner of a pin in particular for the centering effect during the attachment of the pressing tool. In order to prevent the fitting from being compressed by this pressing section when pressing, the latter plunges radially outwards after overcoming the prestressing force, after which the end area of ​​the pressing section facing the fitting can still act actively and / or passively into the pressing.

p0020In the pressing geometry, a radially prestressed pressing section can be provided, which radially deflects in the course of pressing and reaching the prestressing force for adaptation to the remaining pressing geometry. This pressing section can be formed like a pin-like, for example in the form of a spring-loaded pushbutton, in the cooperation area with the fitting; Alternatively, also in the manner of a gauge, extending in the circumferential direction of the fitting in a circular-section-like manner. It is essential that this press section is positioned in the press jaul, that is to say in the region which directly acts on the fitting during the pressing process. Such a prestressed press section serves, in particular, as a centering aid when the pressing tool is placed on a fitting to be pressed. In order to prevent this being damaged during pressing, the prestressed pressing section deviates in the course of pressing and upon reaching or exceeding the pretensioning force, for the purpose of being fitted into the rest. In such an end position, the latter acts in particular radially radially inward and correspondingly radially outwards The pressing part, if necessary, pressingly engages the fitting, either as an active component of the pressing geometry or as a passive element, for example to form an axially acting supporting back. The pretension acting on the pressing section is applied, for example, by a spring, further for example by a cylinder pressure spring. Other elastic elements are also conceivable. It is also provided that, prior to a radial deflection of the prestressed press section, there is no plastic deformation of the fitting, in particular in the immediate contact area with respect to this press section. The pretensioning force (spring force) is correspondingly selected to be such that, by means of this, the pressure portion is released radially radially in the pressed uninfluenced position. Again, the pretensioning force is less than the pressing force, so that the pressing section can deflect radially outward as a result of the pressing and the associated plastic deformation of the adjacent region of the fitting.

p0021The bead geometry allows the bead at least in one direction to flatten the bead, this being achieved by radially influencing the bead, the bead radius being adapted to the cross-sectional diameter of the inserted sealing ring being enlarged in particular in the apex region as viewed in a cross-section of the bead To a radius dimension which corresponds to a multiple of the original radius dimension, so that ultimately even a flat surface cylinder surface on the outer side of the cladding can be adjusted in the apex area of ​​the bead. This is achieved, in particular, by a cylinder section which forms the first pressing geometry. This cylindrical section, viewed in the axial direction, is configured longitudinally in such a way that the space for the axial widening of the bead is provided.

p0022On the end of the bead facing away from the pipe-engaging end of the press-fitting, a gauging section is formed on the pressing tool. This teaching section primarily serves to stabilize the pressing tool relative to the longitudinal axis of the pipe, according to which a relative displacement of the press fitting in the axial direction is also counteracted in the course of the pressing operation. Advantageously, the first pressing geometry is designed in such a way that the gauging section prevents the axial widening of the bead on the side of the bead facing away from the pipe insertion end. Correspondingly, in the course of the pressing operation, the gauging section provides a rear support-a counter-holder-for the first pressing geometry, so that the bead acted upon by the first pressing geometry radially outwards only in one direction, namely in the direction toward the pipe insertion end of the press fitting Can The gauging section is further formed in such a way that this serves merely to stabilize or guide the pressing tool to the pressfitting; But does not transfer pressing forces in the actual sense to the pipe fitting or to the inserted pipe. However, in a preferred embodiment, the gauge section is designed so that it can absorb the forces acting in the axial direction on the adjacent bead in the axial direction in order to retain the desired bead broadening in the direction of the gauge. The obstruction of the bead on an axial widening in the direction towards the end remote from the plug-in side is achieved in an alternative embodiment by means of abutment elements which are formed on the gauging section and point in the direction of the bead. The gauge section does not act directly on the bead, but rather indirectly via the bearing elements. A plurality of, preferably evenly spaced apart, contact elements may be provided over the circumferential length of the gauge section, more preferably the two of them, which are positioned in a diametrical counter-position. Correspondingly, a kind of point-by-point support is achieved. A contact element is adapted to a contour profile of the bead, has, for example, a conical surface facing a bead flank. Thus, the bead may also be cap-like in shape, facing the abutment element.

p0023The second plugging geometry on the plug side for forming the trigger is preferably provided in a region which has a distance from the bead in the direction of the tube-side end of the fitting which corresponds to at least 1.5 times the height dimension or more of the uncompressed bead. For example, in the axial direction, the second pressing geometry is spaced apart from the first pressing geometry, which acts on the bead, by an axial distance which corresponds to 2 to 10 times, more preferably 4, 5 or 6 times the radial bead height Further, for example, 2.1 times or 3.9 times, respectively, 4.7 times. The axial distance dimension relates in each case to the axial section of the respective compression geometry.

p0024A calibrating pressing section is provided between the bead pressing section of the pressing tool and the conical pressing section of the pressing tool and is provided with regard to the radial distance between the bead pressing section and the conical pressing section, whereby the conical pressing section leaves a reduced radial interior space against the bead pressing section and the calibration pressing section leaves a radial interior space whose diameter Is dimensionally between that of the conical-pressing section and the bead-pressing section, so that these diameters are approximately the same as a dimensional average. The calibration press section serves to calibrate the raw-section-shaped area between the pressing sections of the press fitting, so that a preferably strictly cylindrical fitting section also results in this area after pressing. For this purpose, the calibration press section has a cylinder section which, in particular, acts, in the form of a shape correcting, against the associated wall section of the pipe fitting, particularly toward the end of the advanced pressing operation.

p0025This results in a transitional section between the bead pressing section and the calibration pressing section considered in the axial direction. The width of the conical-pressing section approximately corresponds to the difference between the radii of the conical-pressing section and the calibration-pressing section, the axial width of which is approximately the same as the axial width of the conical-pressing section. The transition section between the calibration pressing section and the conical-pressing section is more preferably not stroke-like, step-like, but rather rounded. Alternatively, the axial width dimension of the transition section is selected to be smaller than the axial width dimension of the conical-pressing section, in particular in the case of pressing tools for pressing fixtures with small diameters. For example, the axial width of the transition section corresponds to 0.3 to 0.7 times, more preferably to 0.5 times the axial width of the cone extrusion section. In this transitional section, in a preferred embodiment, the radially prestressed press section is clamped in the pressing state, thus forming at least partially the transition section contiguously at the end face towards the radially inside.

p0026Preferably, two diametrically opposite prestressed press sections are provided, the free ends of which are conically shaped towards the radially inner end, for support on the facing bead edge. The bead flank, opposite thereto, is flanked by the gauging section or by the abutment elements attached to the gage section. If such abutment elements are provided, then two such elements are preferably arranged in a diametrical counter-position, which is further offset by 90 ° relative to the prestressed press sections. In any case, the bead is gripped axially on both sides for centering the pressing tool.

p0027The cylinder portion of the bead pressing portion has an axial length corresponding to a multiple of the axial length of the cone pressing portion, more preferably one of 2- to 5-fold length, more preferably 3-fold, or even 2.4 or 3.2 Times the length of the cone extrusion section. The axial length of the calibrating press portion may further correspond to the axial length of the bead press portion, resulting in the cylinder portion of the calibrating press portion having an axial length corresponding to a multiple of the axial length of the conical pressing portion. This, in turn, has an axial length which corresponds to a 0.5 to 5 times the wall thickness of the press fitting, for example, 1-fold or 3 to 4-fold, further 1.7 or 4.2 The wall thickness of the pipe fitting being 2.5 mm, this further comprising an O-sealing ring with a circular cross-section with a diameter of 5 mm and a corresponding radius adjustment. In the exemplary embodiment of the invention, the wall thickness of the pipe fitting is 2.5 mm Of the bead.

p0028For axial alignment on the end of the pressing tool facing the conical pressing section, an abutment web is provided adjacent to an end face of the press fitting. This acts for the adjustment of the pressing tool and for stabilizing the same during the pressing process against the free end face of the pipe fitting at the pipe insertion end, according to which the press fitting is axially clamped between this bearing web and the teaching section adjoining the rearward side of the bead. On the bead-facing side of the abutment web, there is further provided a second gauging section, which protrudes radially from the outside against the shell outer surface of the tube.

p0029The first gauging section, which is provided on the end of the bead facing away from the pipe-engaging end of the press-fitting, can be partially surrounded by the press-fitting, thus forming a semi-cylindrical section. In a preferred embodiment, the second gauging section provided on the bead-facing side is also semi-cylinder-like, whereby, if necessary, both gauging sections do not necessarily lie over the entire pressing operation over their entire semi-circular contour rearward of the bead or on the tube. Rather, for example, at the beginning of the pressing process for the purpose of merely stabilizing the combination of pressfitting and tube in the pressing tool, punctual supports, in particular diametrically opposing supports of the gauging sections, can be provided from which support points the connecting surfaces of the gauging section and the fitting section or the tube section starting from the support surface In the circumferential direction, so that, towards the end of the pressing operation, the gauging sections, in particular the bead-side gauging section, rest against its entire circumferential line.

p0030The first gauge portion rearwardly associated with the bead has an axial longitudinal extent which is 1.5 times or more the wall thickness of the press fitting, or about 1 to 3 times the axial length of the bead pressing portion, resulting in a sufficient stability of the teaching portion Respectively. Correspondingly, the latter is further provided with an axial length which corresponds to a multiple, for example 2 to 5 times, preferably approximately 3 times the axial length of the conical pressing section.

p0031In a further preferred embodiment, it is provided that the radial dimension of the calibration press section is backward by 0.5 times or more of the wall thickness of the fitting to be pressed, compared to the radial dimension of the conical pressure section. Thus, in a preferred embodiment, this radial distance between the pressing surfaces of the calibration and conical-pressing section corresponds approximately to the fitting wall thickness. Finally, it is provided that the radial dimension of the bead pressing section is increased by 0.1 to 0.9 times the bead height of the unpressed fitting compared to the radial dimension of the calibration pressing section. For example, the radial offset dimension between the press surfaces of the bead and calibration press section for pressing tools for large-diameter fittings is approximately 0.1 to 0.4 times, further about 0.2 times the unpressed bead height, and approximately the same 0.5 to 0.8 times the fitting wall thickness, while for smaller fitting diameters, a radial offset is selected which is approximately 0.5 to 0.8 times, further about 0.6 times the bead height or approximately 1 , 0 to 2.0 times, still approximately 1.5 times the fitting wall thickness.

p0032All the aforementioned dimensions or dimensional ranges or ratios or ratio ranges refer to the indicated values ​​as well as to intermediate values ​​between the minimum and maximum values, in particular also to intermediate values ​​in the tenth range, even if these are not explicitly listed in individual values.

p0033The invention is explained in more detail below with reference to the attached drawing, which merely shows two exemplary embodiments. It shows:<dl id="dl0001"><dt>FIG</dt><dd>A perspective view of a pressing tool according to the invention in the open position, attached to a fitting to be pressed with inserted tube, relating to a first embodiment;</dd><dt>FIG</dt><dd>10 is a further perspective view according to the situation in FIG <figref idrefs="f0001">FIG</figref>; </dd><dt>FIG</dt><dd>In a perspective view the pressing tool in the applied, ready-to-press state, with the fitting inserted, but with the pipe removed;</dd><dt>FIG</dt><dd>A side view against the pressing tool with inserted fitting and tube, leaving the device acting on the pressing tool for pressing;</dd><dt>FIG</dt><dd>Sectional view taken along line V - V in FIG <figref idrefs="f0004">FIG</figref>;</dd><dt>FIG</dt><dd>One to the representation in <figref idrefs="f0004">FIG</figref> Rear view against the pressing tool;</dd><dt>FIG</dt><dd>Sectional view taken along the line VII - VII in FIG <figref idrefs="f0004">FIG</figref>;</dd><dt>FIG</dt><dd>The section taken along the line VIII - VIII in FIG <figref idrefs="f0004">FIG</figref>;</dd><dt>FIG</dt><dd>The enlargement of the region IX in FIG <figref idrefs="f0004">FIG</figref>;</dd><dt>FIG</dt><dd>The detail representation according to <figref idrefs="f0006">FIG</figref> In a perspective view;</dd><dt>FIG</dt><dd>one of the <figref idrefs="f0003">FIG</figref> Corresponding perspective view, but relating to the pressing position;</dd><dt>FIG</dt><dd>The enlarged sectional view according to FIG <figref idrefs="f0006">FIG</figref>, Concerning the pressing position;</dd><dt>FIG</dt><dd>In a perspective, partially sectioned view, the pressing tool in a second embodiment, in an applied, ready-to-use state, with the fitting inserted, but with the pipe removed; </dd><dt>FIG</dt><dd>one of the <figref idrefs="f0004">FIG</figref> Corresponding view representation relating to the second embodiment;</dd><dt>FIG</dt><dd>Sectional view taken along the line XV - XV in FIG <figref idrefs="f0011">FIG</figref>;</dd><dt>FIG</dt><dd>The section taken along line XVI - XVI in FIG <figref idrefs="f0011">FIG</figref>;</dd><dt>FIG</dt><dd>The enlargement of the region XVII in FIG <figref idrefs="f0012">FIG</figref>;</dd><dt>FIG</dt><dd>The enlargement of the region XVIII - XVIII in FIG <figref idrefs="f0012">FIG</figref>;</dd><dt>FIG</dt><dd>The enlarged sectional view according to FIG <figref idrefs="f0014">FIG</figref>, But with regard to the postponement;</dd><dt>FIG</dt><dd>The enlarged sectional view according to FIG <figref idrefs="f0015">FIG</figref> In the pressing position.</dd></dl>

p0034In <figref idrefs="f0001">FIG</figref> Is a perspective view of a first embodiment of the pressing tool 1 according to the invention with tubular workpieces inserted therein, which are to be pressed together. As can be seen in connection with the following figures, these workpieces are a tube 2, which is inserted into a press fitting 3. The workpieces have a common central longitudinal axis x.

p0035In the exemplary embodiment shown, the pressing tool 1 is a kind of press chain, as is known, for example, from the <patcit id="pcit0009" dnum="EP1455969B1"><text>EP 1455969 B1</text></patcit> Is known. The content of this patent is hereby incorporated by reference into the disclosure of the present invention, also for the purpose of incorporating features of this patent in claims of the present invention.

p0036The pressing tool 1 of the embodiment shown consists of four pressing members, which are involved in the pressing operation of the workpieces. For this purpose, the pressing tool 1 initially has two pressing members 4, 5 which are arranged opposite one another in the circumferential direction and can be displaced relative to each other for the purpose of changing a pressing cross section by means of two toggle levers 8 embodied as an angle lever. A articulated lever 6 is connected to a joint lever 7 by means of a knee joint 9, respectively. The articulated lever 6 has an outer joint 10, which is connected to the pressing member 4.

p0037At its opposite end, the articulated lever 7 has an outer hinge 11, which is connected to the pressing member 5. In view of the recognizable axis-symmetrical arrangement of the two toggle levers 8, the same reference symbols are selected for corresponding elements in the following. A further pressing member 12, 13 is provided in the respective circumferential angle range of a joint lever 7, which has a greater length opposite the articulated lever 6, the pressing members 12, 13 also being opposite one another with respect to the pressing cross section.

p0038The pressing members 4, 5 are not connected to the pressing members 12, 13 by means of articulations, but are only held captive on the articulated levers 7 and guided by means of sliding guides on the pressing members 4, 5. This means that the press members regularly surround the press cross-section or the workpieces to be pressed over the complete circumference before the beginning of the pressing operation.

p0039Furthermore, on the lever levers 6, force introduction elements 14 are provided for force introduction outside the outer joint. In the exemplary embodiment shown, the pressing members 5, 12 and 13, as well as the articulated levers 6, each have three parallel-spaced plate regions with parallel joints lying in between. On the other hand, the pressing member 4 and the articulated levers 7 each have two comparable spaced plate portions sized and spaced so as to allow engagement into the joints of the pressing members 5, 12 and 13 and the articulated levers, thereby interpenetrating the same. With respect to the pressing members 4, 5 and 12, 13, the plate regions are integrally connected to one another via press jaws 15, 16, 17 and 18, whereby a stable design is obtained. The illustrated articulated connections between the pressing members 4, 5 and the articulated levers 6, 7 are made by means of terminal bores penetrating through each other in the assembled state, through which cylinder pins are inserted and held at their ends by retaining rings. In the exemplary embodiment shown, it is provided that the press chain can be opened on the knee joint 9 of the upper toggle lever 8 by displacing a coupling pin 19 into a release position.

p0040The pressing operation with a corresponding reduction in the pressure cross-section is achieved by pressure-clamping jaws 20 arranged on a pressing device (not shown) which act on the pressing tool 1 and which are part of pressing levers which are rotatably arranged in a clamping device. The pressing jaws 20 are positively connected to the articulated levers 6 by means of the force introduction elements 14. In the course of a pressing operation, the pressing jaws 20 are applied to the lever-side ends in the rear in such a way that the pressing jaws 20 are clamped in the manner of a tong, which results in a reduction in the spacing of the force introduction elements 14 from one another. By means of a rotation of the articulated levers 6, 7, the press cross-section in the area of ​​the press jaws 15 to 18 is reduced for pressing.

p0041The pressing jaws 15 to 18 are configured to be radially inwardly directed towards the workpieces to be pressed, correspondingly having the same pressing geometries in a cross-section. Such a cross-section through a press jaw is shown in FIG<figref idrefs="f0006">FIG</figref> Respectively.

p0042Each pressing jaw 15 to 18 has a cross section as shown in FIG <figref idrefs="f0006">FIG</figref> A first pressing geometry 21, which is formed by a bead pressing section 22, which is shaped as a cylinder section, extends approximately over one third. The first pressing geometry 21, which is arranged one behind the other in axial alignment of the respective pressing jaw, Of the total length a of the press jaw of the press jaw 15 acting on the pressfitting 3 acting in the direction of the axis x of the press jaw 15 to 18. Thus, for the selected axial length a of the total pressing geometry of approximately 30 mm acting on the pressfitting 3 is one in the same Direction measured length b of the cylinder portion of the bead pressing portion 22 of about 10 mm.

p0043A calibration pressing section 23 is formed in an axial secondary arrangement relative to the bead pressing section 22 approximately centrally over the entire axial length a of the effective pressing geometry. This is also formed by a cylinder section, from which a cross-section according to FIG<figref idrefs="f0006">FIG</figref> As in the case of the bead pressing section 22, a press-acting wall 22 'or 23' running parallel to the axis x results.

p0044The calibration pressing section 23 has a length c measured in the axial direction, which corresponds approximately to the length b of the bead pressing section 22. For example, the calibration press section 23 is provided with approximately one-third of the total length a of the effective press cross-section, so further in the illustrated exemplary embodiment with a length c of approximately 10 mm.

p0045As can be seen more particularly from the sectional view in FIG <figref idrefs="f0006">FIG</figref> The effective surfaces 22 'and 23' of the press sections 22 and 23 run on different radius lines. Thus, the cylinder section forming the bead pressing section 22 is provided with a larger diameter than the cylinder section for forming the calibration pressing section 23. In the exemplary embodiment shown, the radius oversize d between the surfaces 23 'and 22' corresponds approximately to one-fifth of an axial extension length b or c of the press sections 22 or 23. Furthermore, this radius projection d corresponds approximately to the material thickness (dimension e) of the fitting 3 to be pressed .

p0046In the illustrated exemplary embodiment, the pressing tool 1 or the pressing jaws 15 to 18 are designed for pressing a tube 2 having a 4-inch diameter and a correspondingly dimensioned fitting 3. In such 4-inch tubes, fittings 3 generally have a wall thickness E of about 2.5 mm.

p0047A transition section 24 is formed between the bead pressing section 22 and the calibration pressing section 23 in the axial direction. This forms a rounded step of the radius transition between the surfaces 22 'and 23'. The axial width f of this transition section 24 approximately corresponds to the radius oversize dimension d between the surfaces 22 'and 23', is further adapted in accordance with the material thickness of the fitting 3 to be pressed, accordingly has a dimension f of approximately 2.5 mm in the illustrated exemplary embodiment.

p0048In this exemplary embodiment, the radial dimension difference g between the pressing surfaces 23 'and 25' of the calibrated pressing section 23 and the cone pressing section 25 corresponds approximately to the material thickness e of the fitting 2, which is approximately 2.5 to 3 mm, while the radial dimension difference d between the pressing surfaces 22 'and 23' Of the bead pressing section 22 and the calibration pressing section 23 corresponds approximately to 0.2 times the unpressed bead height n.

p0049On the side facing away from the bead portion 22, a second pressing geometry 40 in the form of a conical-pressing portion 25 adjoins the calibration pressing portion 23. This, too, is radially inwardly provided with a cylindrical surface 25 'concentric with the axis x. The cylinder diameter defining this pressure surface is reduced relative to the diameter defining the surface 23 'of the calibrating pressure section 23, for example, by the dimension of the material thickness (dimension e) of the fitting 3 to be pressed. Thus, in the illustrated embodiment a radiance difference g between the surface 25' And the surface 23 'of approximately 2.5 to 3 mm, which results in a radial difference between the conical pressing surface 25' and the bead pressing surface 22 'approximately in the region of the double material thickness.

p0050The axial width h of the conical-pressing section 25 likewise corresponds roughly to the material thickness of the pressfitting 3, and is thus approximately 2.5 to 3 mm in the illustrated exemplary embodiment. The conical-pressing section 25 is formed in the shape of a branch, which extends roughly radially from the surface of the calibration pressing section 23, with an axial dimension approximately corresponding to the radial projection dimension opposite the calibration area 23 '.

p0051At the rear of the cone-pressing section 25, with respect to the calibration pressing section 23, an escape space 26 is left over the remaining length of the compression geometry acting overall on the pressfitting 3. Its cylinder wall is provided with a radial dimension which corresponds approximately to 0.75 times the radial difference dimension g between the conical pressing surface 25 'and the calibration pressing surface 23'.

p0052The pressure jaws 15 to 18 extend in cross-section one end beyond the pressing geometry which essentially acts on the pressfitting 3, to form a contact strip 27 which is formed in the region of the end of the escape chamber 26 remote from the cone pressing section 25. The latter engages radially inward over that through the cone pressing surface 25 ', For cooperation with an facing, tube-side end face 35 of the inserted press fitting 3.

p0053A gauging section 28 is fixed on the cheek surface of the jaw section forming the attachment web 27 and correspondingly on the side of the abutment web 27 facing the bead. In contrast to the three-part design of the press jaws, the latter is integrally formed, forming a semicircular ring in a plan view. This is fastened to the pressing member 5, whereby the semicircular ends of this gauging section 28 in the prepared position according to FIG<figref idrefs="f0003">FIG</figref> Over the pressing members 12 and 13 in sections.

p0054In the case of a material thickness k measured in the axial direction, which corresponds approximately 2.5 mm to the material strength of the pipe fitting 3 in the illustrated embodiment, an internal radius of the annular gauge section 28 is provided which is adapted to the outside diameter of the pipe 2 to be pressed. Correspondingly, the facing end face of the gauge section 28 lies at least partially on the facing jacket section of the tube 2, both in the preparation position and in the pressing position, for the stabilization and radial support of the tube 2.

p0055The axial distance v of the gauging section 28 from the pressure surface 27 of the bearing web 27 and thus in the pressing situation to the supporting end surface 35 of the fitting wall is, for example, dimensioned with the three-dimensional thickness dimension k of the gauging section 28 in the illustrated embodiment. Thus, the distance measure v in the illustrated embodiment is about 7.5 mm.

p0056A further teaching section 29 is also fastened at the other end to the overall pressing geometry, that is assigned to the cheek surface of the pressing member 5 remote from the teaching section 28. This is also semi-circular in shape in a plan view with free ends partially extending over the pressing members 12 and 13. Contrary to the teaching section 28, the teaching section 29 is thickened, correspondingly has a dimension m, which is approximately in the axial direction, approximately three times the thickness dimension k of the gauging section 28, such as about three times the material thickness e of the fitting 3 to be pressed.

p0057The inner radial dimension of the gauge section 29 is adapted to the outer diameter dimension of the fitting 3 to be pressed so that the gauge section 29, at least in the pressed state, comes into semi-circular contact with the associated wall section of the fitting 3. As a result, a radial support of the fitting 3 and also of the tube 2 which is inserted in the fitting 3 is initially achieved.

p0058On the cheek side, that is to say the pressing geometry, in particular the region of the bead pressing section 22, the gauging section 29 forms a conical surface 30. The gauging section 29 is supported on this conical surface 30 on a facing flank 34 of a circumferential bead 31 formed on the fitting 3.

p0059The bead 31 of the press fitting 3 is used to receive an O-sealing ring 32 arranged in the inside, which preferably consists of a rubber-like or rubber-like material. The sealing ring 32 is circular-shaped in cross-section. The bead 31 covers the sealing ring 32 in a cross-section, wherein an apex region 33 of the bead 31 running essentially concentric to the center point of the sealing ring cross-section merges into flanks 34 on both sides in the axial direction of the fitting 3, which flanges run into the fitting cylinder wall.

p0060The pressfitting 3, as shown in the exemplary embodiments, can be a fitting which can at one end receive a tube 2 for pressing, while at the other end the fitting 3 is designed, for example, for welding to a further tube piece or the like. The pressing tool 1 according to the invention and the proposed method can, of course, also be carried out on fittings 3, which are formed in the manner of a sleeve in the manner of a sleeve on both sides at the end side with a press section, as well as press fixtures 3 in the form of a T in which press-fitting with a plug-in tube according to the pressing tool 1 according to the invention All three pipe receptacles, which is due in particular to the small installation space of the tool on the side of the bead 31 opposite the pipe plug-in side of the fitting 3.

p0061In the exemplary embodiment shown, the bead 31, viewed in the axial direction, continues on both sides in fitting cylinder sections, so towards a side in the direction of an opening serving to receive the tube 2. The end face of the press fitting 3 which delimits the end of the press fitting 3 on the tube insertion side is provided with the reference numeral 35.

p0062The axial distance of the bead 31 from the end face 35 on the tube insertion side is adapted to the axial extent a of the effective pressing geometry of the press jaws 15 to 18. Accordingly, the press fitting 3 is pressed into the press jaws in such a way that the bead 31 engages in the region of the bead pressing portion 22 , Which is supported by the flank 34 facing the gage section 29 on the conical surface 30 of the gage section 29. At the end in the axial direction, an axial support takes place between the end face 35 on the fixture side and the abutment web 27, according to which an axial fixing of the fitting 3 to be pressed is carried out in the axial direction Pressing tool 1 is reached.

p0063The tube 2 is pushed into the fitting 3 for compression purposes, this being limited by the impact, which is achieved by a shell-inner-wall step 36 in the fitting 3. The inner diameter of the pipe fitting 3 and the outer diameter of the pipe 2 are adapted to each other, so that the pipe already in the non-compressed state is tipped in the fitting 3 in the fitting 3. In the annular space obtained between the bead 31 and the outer shell jacket, the seal 32 is located, which retains essentially its circular cross-section even after the tube 2 has been inserted.

p0064In the unpressed state, the bead 31 has a radial height n which corresponds approximately to 2.5 to 3 times the wall thickness e of the fitting 3, the radial height n being determined by the radial dimension between the jacket inner wall of the fitting 3 and The radially outer apex of the bead 31.

p0065The cross section diameter of the ring 32 is approximately 5 mm, resulting in a bead width p in the unpressed position measured in the direction of the axis stretching which corresponds approximately to the threefold of the thickness of the material of the fitting, so that in the Is about 8 mm. The measurement points on which this measure is based for defining the width dimension p are as shown in FIG<figref idrefs="f0006">FIG</figref> Approximately in the reversal point from the circular-section-shaped apex 33 into the flanks 34 of the bead 31.

p0066As can be seen further from the illustration in FIG <figref idrefs="f0006">FIG</figref> The bead 31 extends axially, as viewed in the axial direction, with the flank 34 on the cone 30 only over a partial region of the axial extension length of the bead pressing section 22, so that more than two-thirds of this axial length.

p0067In the pressed-in basic position, ie, when the compression chain is already closed, the pressing members 4, 5 and 12, 13 are pressed against the pressfitting 3 in the region of the conical pressing sections 25, this being supported on the end face 35 of the fitting 3 by means of the support web 27.

p0068In this basic position, the two gauging sections 28 and 29 rest against the associated wall sections only in the diametrically opposite end areas of the semi-circular ring-shaped sections approximately in the middle of the circumferential extent of the pressing members 12 and 13. This multi-point contact is indicated by reference numerals 37 and 38 in FIGS. 4 and 5, whereby the contact zones of the gauging section 28 on the tube 2 and the contact zones of the gauging section 29 on the fitting 3 are arranged at the rear of the flank 34 of the bead 31 Respectively.

p0069The arcuate surface of the respective gauging section 28 or 29, which faces the workpiece, extends outwardly from these support points 37 and 38 toward the center of the gauging section, so that the maximum radial distance between the gage section and the assigned workpiece is achieved in the opposite direction to the force introduction elements 14 .

p0070In this position, a stabilization of the pressing tool relative to the longitudinal axis x of the tube is carried out by means of the gauge sections 28 and 29.

p0071In the course of the pressing, in which the press cross-section is reduced, a linear displacement of the gauging sections 28 and 29 takes place in accordance with the displacement of the pressing member 5 so that they offer a circumferentially enlarged radial support of the workpieces to be pressed during the pressing operation.

p0072By the contraction of the pressing jaws, a deformation of the fitting 3 and the pipe 2 in the region of the conical pressing section 25 as well as a deformation in the region of the bead pressing section 22 is achieved. The pressurization of the bead 31 causes an axial widening of the bead 31 from radially outward through the cylinder surface 22 'of the bead pressing portion 22, resulting from a flattening of the apex 33 as well as the limb 34, resulting in a compressed bead width dimension r which is approximately equal to 1 , 5 times the original bead width dimension p, and is further adapted to the axial extension length b of the bead pressing section 22. This results in a bead height s, which is reduced compared to the original radial bead height n, by about the amount of the material thickness e of the fitting 3 The annular space 32 which accommodates the sealing ring 32 is radially reduced which results in a deformation of the O-sealing ring 32 into an elongated cross-section viewed in the axial direction, this being accompanied by an increase in the effective sealing surfaces. Due to the rearward support on the gauge section 29, the axial widening of the bead 31 takes place only in one direction, namely in the direction towards the tube insertion end.

p0073The conical pressing section 25 (measured from the respective axial middle areas of the sections), which is provided with an axial distance t to the bead pressing section 22, effects a deformation of the pipe 2 and the fitting 3 in such a way that a trigger safety device is established. This is illustrated by a cross-sectional view taken along the line A - A in FIG<figref idrefs="f0009">FIG</figref> Shaped V-shaped profile of the wall sections. Facing the bead pressing section 22, the cone-pressing section 25 raises a radially expanding cone section on the pipe side as well as on the hose side, which, in the area of ​​the calibration pressing section 23, merges into a cylindrical section which is axially shortened in comparison to the calibration pressing section 23. The calibration press section 23 serves to form this cylindrical section, not by pressurizing, but rather by forming a cuff which counteracts a deformation deviating from the cylindrical shape.

p0074On the other side of the described cone-shaped conical shape for the triggering of the trigger, the end face 35 facing the tube side faces an equally conically erecting shape which widens towards the tube insertion end. The end section of the fitting 3, which is in this case, is partially immersed in the evacuation space 26, but without losing the support on the resting web 27, which is provided with a corresponding inclined flank 39 to allow this radial thrusting.

p0075The axial distance between the axial center region of the compressed bead 31 and the reversing zone of the generally V-shaped jacket wall sections of the fitting 3 corresponds to the above-described axial spacing dimension t between the bead pressing section 22 and the cone pressing section 25. The axial distance measured from this V- To the end face 35 corresponds approximately to 0.4 times the axial dimension t in the exemplary embodiment illustrated, so that the three-fold of the material thickness e of the fitting 3, for example.

p0076The illustrated and described exemplary embodiment shows a pressing tool 1 in the form of a press chain. In particular, for smaller tube and fitting diameters, however, it is also possible to use pressing tools which are provided in the manner of a tong, with two half-shell-shaped pressing jaws having the above-described pressing geometry.

p0077The <figref idrefs="f0010 f0011 f0012 f0013 f0014 f0015 f0016 f0017">Figures 13 to 20</figref> Show a second embodiment of the pressing tool 1 according to the invention which, like the first embodiment, has four pressing members, which are involved in the pressing process of the workpieces, in the manner of a pressing chain.

p0078The basic construction of this pressing tool 1 of the second embodiment essentially corresponds to that of the previously described exemplary embodiment, for which reason the same components, component groups or dimensions bear the same reference symbols.

p0079The pressing tool 1 of the second embodiment is designed for the pressing of fittings 3 and tubes 2 of smaller diameter, for example with a diameter of 1.5 inches. However, the following constructive solutions are also applicable to pressing tools 1 for compressing fittings 3 and tubes 2 of increased diameter, as described, for example, by means of the first exemplary embodiment.

p0080The pressing jaws 15 to 18 of the pressing tool 1 according to the second embodiment are extended by the axial dimension a of the total pressing geometry compared with those of the first embodiment. This is exemplified in<figref idrefs="f0014">FIG</figref> By means of the pressing jaw 18, wherein, as in the first embodiment, the pressing geometries described in this respect are formed on all pressing jaws.

p0081The press jaw 18 of the second embodiment is laterally flanked by the gauges 28 and 29. As also in the first exemplary embodiment, the second pressing geometry 40 is directly adjacent to the gauging section 28, to which second pressing geometry, in the axial direction, the first pressing geometry 21 follows. A pressing jaw section 45 is left between the first pressing geometry 21 and the gauge section 29 facing away from the free end of the fixture. This has an axial length j, which corresponds approximately to the axial length c of the calibration press section 23.

p0082The extended press jaw section 45 is partially radially enlarged relative to the adjacent bead pressing section 22, such as about the radius oversize dimension d between the pressing surfaces 23 'and 22' of the calibrating press section 23 and the bead pressing section 22, the radius oversize dimension d in this embodiment being approximately 1.5 times Of the material thickness e of the fitting 3 to be pressed. Furthermore, the radial oversize d corresponds approximately to 0.5 times the bead height n measured in the radial direction in the unpressed state.

p0083The press jaw section 45, which adjoins the bead pressing section 22 in the direction of the gage section 29, is not involved in the pressing geometry; Acts in a non-deforming manner on the fitting 3 in the course of the pressing operation.

p0084The radial expansion in the region of the press jaw section 45 is not provided over the entire circumferential length of this section 45, but rather with respect to the entire pressing tool 1 only in two diametrically opposite areas, specifically in the center of the circumferential extensions of the pressing members 12 and 13 or the press jaws 17 and 18, so as to be in the form of bore-like pockets 46 which extend axially from the gauging section 29. These are covered by their flanking gusset section 29, which is also arranged in this embodiment as shown in FIG <figref idrefs="f0011">FIG</figref> In a plan view is approximately semi-circular.

p0085The gauging section 29, facing the pressing jaw section 45, further contributes to the pockets 46 of the abutment elements 47. These are provided with an axial depth which corresponds approximately to 0.8 times the length j of the jaw section 45 measured in the self-direction. The two diametrically opposite abutment elements 47 are initially designed in the manner of a pin, with a base 48 held in the gage section 29. This base 48 carries a cap section which is enlarged in diameter relative thereto and which has a peripheral conical surface 30 adapted to the bead flanks 34 towards the free end. The arrangement and configuration of the abutment elements 47 is selected in such a way that, in a position prepared for compression, as shown in FIG<figref idrefs="f0014">FIG</figref> The conical surface 30 of the respective abutment element 47 is braced against the bead flank 34 facing away from the free end of the fixture and thus takes over the function of the conical surface 30 of the gaging section 29 according to the first embodiment.

p0086Viewed over the circumference of the crimping jaw 18 or the opposing crimping jaw 17, the respective crimping jaw section 45 is radially selected such that its radially inner surface coincides with the pressing surface 22 'of the bead crimping section 22 outside the pockets 46. This applies to the press jaws 15 and 16 over their respective entire circumferential section (cf.<figref idrefs="f0015">FIG</figref>).

p0087As viewed in the circumferential direction, the pressing members 4 and 5 in the region of their pressing jaws 15 and 16 each have a radially prestressed pressing section 49 in the form of a pin-like, radially spring-loaded element.

p0088This pressing portion 49 is positioned between the calibrating pressing portion 23 and the bead pressing portion 22 as seen in the axial direction in the region of the transition portion 24. [ For this purpose, a radial bore 50 is provided which is covered radially outward by caps 51, for example screw caps. The bore 50 tapers radially on the inside and runs open into the press chamber.

p0089In the bore 50, specifically in the diameter-enlarged region, there is in each case a pressure spring 52, which presses the press section 49 radially inwards. For this purpose, the pressing section 49 has a plate section 53 which is enlarged in diameter relative to the free radially inwardly extending section. This is accommodated in the bore 50 in a diameter-adjusted manner. The pressure spring 52 acts on this plate, which plate 52 at the same time acts as a limiting stop.

p0090Each press section 49 is formed as a circular cylinder with a conically shaped tip 54, the cone angle being adapted to the angle of a facing bead flank 34. The diameter of each press section 49 corresponds approximately 1.2 times the axial length c of the illustrated embodiment Calibration pressing section 23.

p0091In order to prepare a pressing operation, the fitting 3 together with the pipe 2 according to the first embodiment is inserted into the pressing tool 1, whereafter a centering of the pressing tool 1 for the fitting takes place via the two teaching-side contact elements 47 and the two prestressed pressing sections 49 offset by 90 ° in the circumferential direction 3, in particular to the bead 31, is reached. The bead 31 or the opposing bead flank 34 is urged against the conical surfaces 30 of the abutment elements 47 by the press-sections 49, which are spring-loaded in the radially inward direction, via the abutment against the associated bead flank 34, resulting in self-centering.

p0092In the case of this embodiment too, a deformation of the fitting 3 and the pipe 2 in the region of the conical pressing section 25 as well as a deformation in the region of the bead pressing section 22 is achieved in the course of the pressing by the contraction of the pressing jaws. The pressure loading of the bead 31 causes an axial widening of the bead 31 from radially outside through the cylinder surface 22 'of the bead pressing portion 22, resulting from a flattening of the apex 33 as well as of the limb 34, from which a compressed bead width dimension r (cf.<figref idrefs="f0016">FIG</figref>) Which is approximately 1.3 times the original bead width dimension p. The annular space accommodating the sealing ring 32 is radially reduced, which results in a deformation of the O-sealing ring 32 into an elongated cross-section viewed in the axial direction, this being accompanied by an enlargement of the effective sealing surface.

p0093The shaping of the pipe 2 and fitting 3 in the region of the cone pressing section 25 is also designed in accordance with the deformation according to the first exemplary embodiment.

p0094The abutment elements 47, which are fastened in the teaching section 29 and point in the direction towards the bead 31, cause at least partially a deformation of the bead 31 in the course of the pressing operation only in the direction of the free insertion end of the fitting 3 according to the corresponding support of the bead 31 on the conical surface 30 of the Section 29 in the first exemplary embodiment.

p0095In the course of the pressing process, the spring-loaded pressing sections 49 are inserted radially outward into the bore 50, overcoming the spring force acting on them at the rear. This radial displacement of the pressing sections 49 takes place before compression of the area cooperating directly with these pressing sections 49 in order to avoid damage to the fitting 3 and / or the pipe 2. The spring force of the respective compression spring 52 is counted in this case in such a way that the tip 54 of each pressing section 49 is always in contact with the facing flank 34 of the bead 31, but also by the axial widening of the bead 31 during the pressing, 34 a radial component acting on the associated press section 49 radially outwards. By means of the press sections 49, the desired centering of the pressing tool 1 and the pipe / fitting arrangement is also provided during the pressing operation.

p0096On the one hand, this is due to the selected, relatively large cylinder diameter of the pressing sections 49, but also due to the full-surface support on the borehole wall, which is viewed at least approximately half the circumference of the press section 49 in the direction of the insertion end of the fitting 3, over the entire pressing operation A sufficient support of the press sections 49 is provided. The forces acting in the course of the pressing operation via the axially expanding bead 31 not only with respect to the fitting axis but also axially to the pressing section 49 can thus always be dissipated into the solid pressing jaw 17 or 18 over a large area. Correspondingly, no or negligibly small shearing forces act on the press sections 49.