EP2265415B1 - Method for the permanent connection of workpieces - Google Patents

Description

The invention relates to a method for non-detachable joining of workpieces using a pressing tool. This method can be performed with a pressing tool for non-detachable joining of workpieces with two pivoting elements each having a pressing jaw and with at least one axis of rotation on which the pivoting elements are articulated, wherein the inner contours of the opposing pressing jaws form a receiving area. Furthermore, an attachment for a pressing tool with two pressing jaws, wherein each pressing jaw has an inner contour and wherein the opposing inner contours of the pressing jaws form a receiving area, is described.

Press tools, attachments for pressing tools and methods of the type mentioned are already known from the prior art, for example from the drinking water or heating installation area. Preferably, the tools and methods are used to radially compress workpieces such as fittings, pipes, sleeves or the like. Pressing radially means essentially to transform by means of a pincer-like closing movement of two pressing jaws exhibiting pivoting two two at least partially arranged in overlapping workpieces and thus inextricably linked together.

However, this procedure can be disadvantageous. With provided for this purpose pressing tools and methods is For example, the exercise of an all-round homogeneous pressing force on the workpieces to be pressed significantly difficult. Preferably, pipes and fittings have a rotationally symmetric and largely round shape before the pressing process. However, after the pressing process, this symmetry may be disturbed due to inhomogeneously acting pressing forces at the connection point between the pipe and the fitting, which on the one hand can impair the visual impression as well as the functionality of the connection.

Furthermore, the materials, especially plastics or metals of the claimed in the pressing workpieces can have a directed against the pressing forces inertia. This inertia can lead, in the form of restoring forces, to the fact that the material formed during the pressing process at least partially endeavors to restore the starting state or the starting structure of the workpieces. This requires the user of a radially inward pressing process to have to increase the radially inwardly applied pressing forces to obtain the desired pressing result. However, this is beyond the actual extent beyond and therefore generally undesirable use of the materials to be pressed workpieces.

For example, is from the DE 101 44 100 C1 a pressing tool with two radially mutually engageable pressing jaws for producing a permanent, tight pipe press connection known. The inner contours of the pressing jaws have wedge-shaped surfaces, by means of which the conversion of a radial movement of the pressing jaws in an axial compression of the annular bead of a fitting can be effected.

From the DE 198 40 668 C1 is a pipe joint consisting of a press fitting element, which has at least one cross-sectionally bead-shaped, a sealing ring receiving portion, and from a tube which is inserted into the press fitting element known. The bead-like region is pressed radially with a pressing tool, so that the sealing element is pressed against the tube and thus produces a tight and permanent connection.

From the GB 2 205 373 A a method for connecting pipes according to the preamble of claim 1 is known. For this purpose, a connecting tool is provided, which has two clamping elements with bevelled surfaces, which serve for the radial deformation of the workpiece.

From the DE 27 25 280 A1 Furthermore, a pipe joint of a pipe and a fitting sleeve is known, wherein the fitting sleeve has an inwardly radially open, containing a sealing ring annular bead. This annular bead is compressed with a pressing tool so that the sealing ring is pressed against the pipe inserted into the fitting sleeve. The mold insert of the pressing tool in this case has conical side surfaces which bear against the sides of the annular bead during compression, cause the compression of the annular bead and deform the sealing ring radially.

The aforementioned problems can be solved or at least mitigated, in particular, by means of an axial compression technique. A homogeneous application of force is much easier to ensure in an axial pressing process. Although the restoring properties of the materials to be deformed also act in the axial direction in principle, the effects of increased stress on the material can usually be attributed to radial expansion in comparison to radial expansion long axial extent of the workpieces are kept low. A disadvantage of axially acting pressing tools, however, is that they occupy a wide mounting space and have a high weight. The use of such tools or the application of such methods is difficult for the installer.

The present invention is therefore based on the technical problem of specifying an alternative method with which a permanent connection between workpieces by axial compression can be created.

According to the present invention, the technical problem is solved by a method for permanent connection of workpieces using a pressing tool in particular as described above, wherein the pressing tool is actuated radially inwardly, wherein at least one of the pressing tool disposed against the workpiece axis inclined sliding surface and a Workpiece surface are brought into abutment with each other, in which the radially inwardly exerted pressing force is transmitted from the sliding surface to the workpiece surface and at least partially deflected in the axial direction and in which the workpieces are pressed in the axial direction.

The sliding surface preferably faces a correspondingly adapted workpiece surface. As a result, in particular a larger contact surface between sliding surface and workpiece surface is created. In this way, for example, the stability of the pressing process can be increased.

With regard to further advantages of the method according to the invention is based on the subclaims or on the referenced below to a pressing tool or to a suitable attachment for pressing tools.

The method explained above can be carried out with a pressing tool for non-releasably connecting workpieces with two pivoting elements each having a pressing jaw and with at least one axis of rotation on which the pivoting elements are articulated, wherein the inner contours of the opposed pressing jaws form a receiving area, wherein the inner contours have at least one inclined against the receiving area axis sliding surface.

The receiving area axis runs approximately perpendicularly to the surface located between the inner contours of the pressing jaws and substantially corresponds to the axis of a workpiece insertable for the purpose of pressing into the receiving area, for example a pipe or fitting.

By virtue of the sliding surface inclined in relation to the receiving region axis, the dynamics of a radially inwardly directed movement can be at least partially converted into a pressing force extending in the axial direction. During the pressing operation, the pivoting elements and in particular the pressing jaws are moved toward one another about the axis of rotation, while the workpieces to be pressed are arranged in the receiving region between the pressing jaws. The inner contours of the pressing jaws are brought into contact with surfaces arranged on the workpieces to be pressed. By continuing the radially inward movement, the area remaining between the workpieces and the inner contours is narrowed. The lying in contact with the workpieces sliding surfaces thus act as Kraftübertragungs- and Kraftumlenkungsflächen, because the sliding surface and the surface slide on the workpiece over each other while the workpiece is set in motion. In this way, although starting from a radially inward movement, a relative movement between the workpieces to be compressed in the axial direction can be generated and used for pressing.

As a result, a pressing tool can be provided which performs a compression in the axial direction, yet takes little mounting space and, for example, by a smaller axial expansion offers weight advantages.

It is possible to provide the inner contour of each pressing jaw with exactly one sliding surface. In this case, however, the inner contour preferably also has a projection acting as an abutment, which is arranged opposite the sliding surface on the other side of the inner contour of the pressing jaw. Preferably, this projection can engage behind a portion of a workpiece to be compressed, in particular of the workpiece, which is not in contact with the sliding surface, and thus build up the counter-pressure necessary for the axial compression. A force deflection from a radially inward in an axial direction is not effected by the projection.

But it is also possible to provide two inclined against the receiving area axis, facing sliding surfaces. In this way, the deflected and applied for axial compression force can be increased. With symmetrical design of the two sliding surfaces and corresponding interaction surfaces on the workpieces, the deflected pressing force is for example doubled. It should be noted, however, that the configuration of the two sliding surfaces not each other or symmetrical, but may be different if it is convenient for the application.

It is particularly advantageous if at least one sliding surface is designed as a cone segment. In this way, in particular the production of the inner contours of the pressing jaws and optionally the production of workpieces with adapted to these pressing jaws interaction surfaces, which are provided for the previously described type of pressing, simplified. As a result, a high degree of compatibility between the pressing tools described above and the workpieces to be pressed, such as pipes, fittings and the like, can be achieved.

Preferably, the angle of inclination of the sliding surface relative to the receiving area axis is between 35 ° and 55 °, in particular at 45 °. The angle of inclination essentially determines the distance of the radially inward movement which is to be covered in order to effect an axial movement over a certain distance. The flatter the angle of inclination, the further the inner contour of the pressing jaw has to reach in the axial direction in order to achieve a certain pressing result, whereas the radial extent of the pressing jaw can be made quite narrow. An angle of, for example, 35 ° thus causes a quite efficient from the radial movement force deflection, whereas an angle of 55 °, although a longer radial path result, but ensures a higher stability during compression. The angle of 45 °, in turn, is particularly suitable to compensate between the two effects. In addition, the outer dimensions of the pressing jaws can be optimized in this way both in the radial and in the axial direction.

It is further particularly preferred that the sliding surface is designed to promote sliding. In this way, the inertia, which oppose the workpieces to be compressed to an axial evasive movement, at least be reduced, so that the pressing operation is easier to perform. The sliding surface to form sliding, can be done in different ways. It is possible to form the portion of the inner contour of the pressing jaw, which comprises the sliding surface, in two parts with the rest of the pressing jaw, and to manufacture the sliding surface of a material such as polytetrafluoroethylene or the like. However, it is also possible to increase the slipperiness by means of a sliding-promoting coating of the sliding surface, for example with a bonded coating. Likewise, it is possible, by smoothing the sliding surface, for example by polishing the sliding surface to form this slide-promoting.

The pressing tool may have an attachment for a pressing tool with two pressing jaws, wherein each pressing jaw has an inner contour and wherein the opposing inner contours of the pressing jaws form a receiving region and the inner contours have at least one sliding surface inclined towards the receiving region axis.

In this way, originally provided for the radial compression pressing tools can be made suitable for axial compression in a simple manner. The new production of the changed requirements correspondingly adapted pivoting elements is therefore no longer necessary, resulting in particular economic benefits.

Fig. 1a,b

ein Ausführungsbeispiel des Presswerkzeugs vor dem Pressvorgang in zwei unterschiedlichen Ansichten,

Fig. 2a,b

das Ausführungsbeispiel des Presswerkzeugs aus den Fig. 1a, b nach dem Pressvorgang in zwei unterschiedlichen Ansichten und

Fig. 3

ein weiteres Ausführungsbeispiel der Anwendung eines Presswerkzeugs.

In the following the invention will be explained in more detail with reference to embodiments illustrated in a drawing. In the drawing show:

Fig. 1a, b

An embodiment of the pressing tool before the pressing process in two different views,

Fig. 2a, b

the embodiment of the pressing tool from the Fig. 1a, b after the pressing process in two different views and

Fig. 3

another embodiment of the application of a pressing tool.

Fig. 1a shows a pressing tool 2 in a side view. The pressing tool 2 has two pivoting elements 4, which are pivotable about an axis of rotation 6 associated therewith. By providing two axes of rotation 6, the pivoting movements of the pivot elements 4 can be made more flexible. However, the provision of only one axis of rotation 6, to which both pivoting elements 4 are articulated, is also possible. By the pivot elements 4 in this example associated support members 8, the pivot elements 4 are interconnected. At a portion of the pivot elements 4 press jaws 10 are arranged, which form a receiving area 12 opposite to each other between them by means of their inner contours. Depending on the position of the pivoting elements 4, the receiving region 12 can be kept closer or closer to one another. In this exemplary embodiment, a tube end 16 encompassed by a sleeve 14 and a fitting 18, which are particularly suitable for axial compression, are introduced into the receiving region 12. The sleeve 14 is is connected to the pipe 16 by fixing protrusions (not shown) disposed on the inner peripheral surface of the sleeve 14, which are anchored in the outer peripheral surface of the pipe 16, so that the sleeve 14 and the pipe 16 are not movable relative to each other.

The following describes the pressing process. Of course, the pressing tool 2 or the method according to the invention is not limited to the use of the tubes 16, sleeves 14 or fittings 18 shown here by way of example.

The swivel elements 4 shown here by way of example can also be provided with removable pressing jaws 10. In this way, by means of an attachment for a pressing tool 2 already manufactured pressing tools 2, which were originally intended for a radial compression, are made suitable for axial compression.

Fig. 1b shows in a cross-sectional view of the arrangement Fig. 1a a fitting 18, a sleeve 14 and a tube 16 before a permanent connection between these three workpieces 14, 16, 18 is made.

The inner contours of the pressing jaws 10 have, in this example, two inclined sliding surfaces 22 inclined towards the receiving area axis 20. Both sliding surfaces 22 are formed in this example as cone segments. However, other shapes are also conceivable. In particular, the angle of inclination of the sliding surfaces 22 can be chosen freely. However, the inclination angle of the sliding surfaces 22 relative to the receiving area axis 20 in this example is constant at about 45 °. Deviations from this value, for example to 35 ° or 55 ° or however, where appropriate, they are also possible. In this embodiment, not shown, the sliding surfaces 22 may be formed, for example, by means of a slide to promote sliding.

The fitting 18 has centrally on its base a recess 24 with bevelled side walls. The angle of inclination of the side walls in this example is advantageously adapted to the angle of inclination of the sliding surfaces 22 on the pressing jaws 10. Further, the sleeve 14 at its flange-like projection on a chamfer 26, which is also adapted to the inclination angle of the sliding surfaces 22, so in this example about 45 °. In this way, the pressing process can be stabilized in particular. Before the pressing operation, the sliding surfaces 22 are in contact with the aforementioned workpiece surfaces, for example the chamfer 26 of the sleeve 14 or the side wall of the recess 24 of the fitting 18th

Fig. 2a shows the state of the pressing tool 2 and the workpieces 14, 16, 18 after the pressing process in a side view. The pivot elements 4 are pivoted inwardly, so that the abutment surfaces 28 of the pressing jaws 10 abut each other.

Fig. 2b turns off the arrangement Fig. 2a In a cross-sectional view. By the radially inward movement of the pressing jaws 10, the force exerted was at least partially transmitted via the abutting sliding surfaces 22 and workpiece surfaces of the pressing tool 2 on the workpieces, in this example, the sleeve 14 and the fitting 18 and in deflected the axial direction. This has the consequence that in this example, the sleeve 14 and the with the Sleeve 14 connected tube 16 and the fitting 18 to each other to move, or in other words, be compressed or pressed.

After the axial pressing operation, a latching projection arranged on the outer circumferential surface of the sleeve 14 is latched in a latching groove arranged on the inner peripheral surface of the outer body of the fitting 18, so that axial removal of the tube end 16 from the fitting 18 engaged by the sleeve 14 is not possible.

The permanent connection is made with it. An axial movement of the tube 16 out of the fitting 18 is prevented by the latching. The support body of the fitting 18 was at least partially molded into the inner peripheral surface of the tube 16 during the pressing operation and thus seals the connection between the tube 16 and the fitting 18, for example against fluids (not shown) guided in the tube 16 under pressure.

As a result, a pressing tool 2 has been used which, despite the radial output movement of the pressing jaws 10, performs a pressing in the axial direction, requires little installation space and, in particular, offers improved handiness.

Fig. 3 shows in a cross-sectional view of an assembly of a pipe 16, a support body having a fitting 18, wherein the support body engages the tube 16, a arranged on the tube outer peripheral surface transmission element 30 which is a wedge shape in cross section and at the wider end of the wedge an opening 32 to has visual control of the pressing state, and an outside of the Transmission element 30 abutting sliding sleeve 34, which is also formed in cross-section also approximately wedge-shaped, but at the wider end has a flange-like projection 36. The flange-like projection 36 of the sliding sleeve 34 has a chamfer 38, the surface of which is provided for interaction with one of the sliding surfaces 22 of the pressing jaws 10 shown schematically in this example. The sliding sleeve 34 includes an opening for visually checking the pressing state of the workpieces 16, 18, 30 and 34. The fitting 18 has on its base a recess 24 with an inclined wall surface, wherein the inclination of the inclined wall surface to the inner contour of the pressing jaws 10th is adjusted.

The pressing jaws 10 in this example comprise two mutually facing sliding surfaces 22, which are formed as cone segments, and have an angle of inclination relative to the receiving area axis 20 of about 60 °. By choosing this slightly higher angle, in particular the stability of the pressing process can be improved.

During the pressing operation, the sliding surfaces 22 of the pressing jaws 10 interact with the inclined wall surfaces on the recess 24 of the fitting 18 and with the chamfer 38 of the flange-like projection 36 of the sliding sleeve 34. The dynamics brought about by a radially inward movement of the pressing jaws 10 is transmitted via the sliding surfaces 22 transmitted to the sliding sleeve 34 and the fitting 18, so that the fitting 18, the sliding sleeve 34 and thus also the transmission element 30 are pushed together in the axial direction. The wedge-shaped design of the sliding sleeve 34 and the transmission element 30 and their conditioning effect that the pressing forces during the pressing process transmitted to the tube outer peripheral surface and be at least partially redirected in radially inward direction. Thereby, the tube 16 is pressed to the support body of the fitting 18, wherein material of the tube 16 is formed in particular in arranged on the outer peripheral surface of the support body recesses 40, so that an axial movement is prevented after the completion of the pressing operation. In this way, thus a permanent permanent connection between a pipe 16 and a fitting 18 can be created.

Claims (7)

1. A method for the permanent connection of workpieces from the drinking water sector or heating installation sector such as fittings, pipes, bushings or the like by using a pressing tool, - in which the pressing tool is actuated radially inward,

   - in which at least one slide face arranged on the pressing tool and inclined relative to the workpiece axis and one workpiece face are brought into abutment to one another, characterized in that

   - the radially inwardly exerted pressing force is transmitted from the slide face onto the workpiece face and is at least partially deflected in axial direction, and

   - the workpieces are pressed together in axial direction.
2. The method according to claim 1,
   in which the slide face is opposed by a correspondingly adapted workpiece face.
3. The method according to claim 1 or 2,
   in which at least one slide face is formed as cone segment.
4. The method according to any one of the claims 1 to 3,
   in which the pressing tool has two slide faces which are inclined relative to the receiving area axis and which face one another.
5. The method according to any one of the claims 1 to 4,
   in which the slide faces are formed as cone segments and the inclination angle relative to the receiving area axis is approximately 60°.
6. The method according to claim 1 or 4,
   in which the deflection is effected through an angle between 35° and 55°, in particular 45°.
7. The method according to claim 1 or 6,
   in which the slide face of the pressing tool is configured in a slide promoting manner.

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