EP0671985B1 - Pressing tool - Google Patents

Abstract

PCT No. PCT/EP93/03302 Sec. 371 Date Jun. 2, 1995 Sec. 102(e) Date Jun. 2, 1995 PCT Filed Nov. 25, 1993 PCT Pub. No. WO94/12297 PCT Pub. Date Jun. 9, 1994Disclosed is a press tool for pressing tubular inner and outer nested workpieces (e.g. a pipe end upon which is slid a press fitting). The press tool includes a plurality of clamping components which contain clamping jaws having a continuous circumferential pressing groove (63) shaped in their inner sides, the jaws having a pressing land (65) that extends along only one side of the pressing groove. The press tool also includes a template (44) which fits over the inner nested workpiece but not over the outer slid-on workpiece, the template (44) being positioned on the side of the groove (63) opposite the pressing land (65).

Description

The invention relates to a pressing tool for pressing tubular, nested workpieces, in particular a pipe end and a press fitting plugged over them, with a plurality of press jaw elements which carry press jaws, into which a press groove which runs in the circumferential direction on the inside and which has a press web along only one side is formed.

To connect pipe ends, it is known to use sleeve-shaped press fittings which are plastically deformable and made of metal, preferably steel. Such pipe connections and the associated press fittings can be found, for example, in DE-C-1 187 870̸ and DE-C-40̸ 12 50̸4.

Various forms of press tools have been developed for the radial pressing of press fitting and pipe end. These pressing tools have pressing jaw elements which have pressing jaws which are moved radially during the pressing to form a closed pressing space. Not only are press tools known with two press jaws (DE-A-34 23 283; DE-A-38 33 748), but also with more than two press jaws in order to be able to achieve higher press-in depths. The latter pressing tools can be found in particular in EP-A-0̸ 451 80̸6. Of particular interest are the pressing tools shown in Figures (7) and (8), since they are suitable for connecting pipe ends of larger and very large diameters.

As can be seen from the generic DE-C2-38 33 748, have the pressing jaws of such pressing tools have a certain cross-sectional contour adapted to the shape of the press fitting. Since such press fittings have an outwardly projecting annular bead at the free end, into which a sealing ring is inserted on the inside, the press jaw has a molded-in press groove for receiving this annular bead. The individual sections of the press groove in the press jaws complement each other to form a continuous press groove.

In order not only to press the ring bead onto the pipe end, but also to cause a compression between the press fitting and the pipe end in addition to the ring bead, press ridges run on both sides of the press groove, which are pressed into the material of the press fitting and thus also of the inserted pipe end during the pressing process. As can also be gathered from DE-C2-38 33 748, the provision of press bars on both sides of the press groove is not absolutely necessary for the functioning of the pressing. However, the handling is foolproof if the cross-section of the press jaws is symmetrical, that is to say the press ridges run on both sides of the press groove, since it does not matter in which position the press tool is placed at the point to be pressed.

When using a pressing tool of the type mentioned at the outset with a symmetrical cross-sectional contour of the pressing jaws, it has been shown that the pressing web lying on the free side of the pressing fitting also comes into contact with the pipe in the final phase of the pressing process and there leads to a constriction of the pipe. Apart from the fact that this increases the pressing forces to be applied, the elastic prestressing of the sealing ring produced by the compression of the annular bead is reduced, so that it is no longer guaranteed that the required tightness is maintained for years. In the worst case, a gap can even arise in the sealing seat area, which leads to leaks.

The invention is therefore based on the object of designing a pressing tool of the type mentioned at the outset which, while maintaining the assembly security, permits pressing without endangering the tightness.

This object is achieved in that a jig is arranged on the other side, which fits over the inserted workpiece, but not over the pushed-on workpiece.

With a press tool designed in this way, foolproof handling is ensured despite the fact that a press web is present along only one side. The advantages of press tools with asymmetrical press jaws can thus be realized without the assembly safety thereby suffering. The advantages are that deformations of the tube in the region of the free end of the press fitting are avoided and the elastic prestressing of the sealing ring as a result of the compression of the annular bead is not impaired. Assembly safety and the guarantee of tightness over the years thus complement each other.

It should be noted that a specific pressing tool only fits for pressing a workpiece with a certain diameter, so the reference to the workpiece also contains a statement about the dimensioning of the pressing tool. The additional arrangement of a gauge prevents the press tool from being placed on the press point in the wrong position, in which the press web comes to rest on the side of the annular bead facing the free end of the press fitting, because in this position the gauge prevents it from touching down, because they don't have that Press fitting fits. Only in the reverse position, in which the gauge comes to lie outside the press fitting, is it possible to put the press tool on.

The teaching consists in a particularly simple design of a correspondingly shaped sheet metal part which is attached to one of the press jaw elements.

Figur (1)

den Preßring eines Preßwerkzeuges in geöffnetem Zustand;

Figur (2)

den Preßring gemäß Figur (1) in geschlossenem Zustand;

Figur (3)

einen Schnitt durch das Kupplungsglied des Preßrings gemäß den Figuren (1) und (2) in den Ebenen A-B in lockerer Kupplungsstellung;

Figur (4)

das Kupplungsglied in der Darstellung gemäß Figut (3) in gespanntem Zustand;

Figur (5)

den Preßring gemäß den Figuren (1) bis (4) in der Stellung nach der Verpressung und

Figur (6)

den Preßring mit Rohrende und Preßfitting in einem Axialschnitt in aufgesetztem Zustand.

In the drawing, the invention is illustrated in more detail using an exemplary embodiment. Show it:

Figure (1)

the press ring of a press tool in the open state;

Figure (2)

the press ring according to Figure (1) in the closed state;

Figure (3)

a section through the coupling member of the press ring according to Figures (1) and (2) in the planes AB in a loose coupling position;

Figure (4)

the coupling member in the illustration according to Figut (3) in the tensioned state;

Figure (5)

the press ring according to the figures (1) to (4) in the position after the pressing and

Figure (6)

the press ring with pipe end and press fitting in an axial section in the attached state.

In the figures (1), (2) and (5), an inner pipe end (1) and a press fitting (2) with a ring bead (3) containing a sealing ring are indicated in cross-section and in a dot-dash line. Pipe end (1) and press fitting (2) should be pressed using a press tool (4) be pressed, of which only the press ring (5) is shown in Figures (1), (2) and (5).

In this exemplary embodiment, the press ring (5) has essentially identical press jaw elements (6, 7, 8, 9, 10ildete), each press jaw element (6, 7, 8, 9, 10̸) consisting of an external press jaw carrier (11, 12, 13, 14, 15) and an inner, arc-shaped press jaw (16, 17, 18, 19, 20̸). With one exception, the press jaw supports are connected to one another via intermediate pieces (21, 22, 23, 24), the press jaw supports (11, 12, 13, 14, 15) using articulated bolts (26, 27, 28, 29, 30̸, 31, 32, 33) are articulated on the intermediate pieces (21, 22, 23, 24).

At least one hinge pin (26, 27, 28, 29, 30̸, 31, 32, 33) per intermediate piece (21, 22, 23, 24) is designed to be removable, so that the press ring (5) is divided into individual press jaw elements (6, 7, 8, 9, 10̸) can be taken apart or assembled on site. The press jaws (16, 17, 18, 19, 20̸) are slidably mounted in the circumferential direction in the press jaw carriers (11, 12, 13, 14, 15).

A clamping device (34, 35, 36, 37, 38) is attached to each press jaw support (11, 12, 13, 14, 15), which has a clamping punch (39, 40̸, 41, 42, 43). The clamping devices (34, 35, 36, 37, 38) also serve to axially guide the press jaws (16, 17, 18, 19, 20̸).

The hinge pins (29, 30̸) on the central press jaw support (13) carry a jaw-like gauge (44) in the form of a sheet metal part with a semicircular recess (45), the radius of the recess (45) being such that the gauge (44 ) fits on the one hand over the pipe end (1), but on the other hand does not fit over the cylindrical part of the press fitting (2) adjoining the annular bead (3). This ensures that the Press ring (5) can only be put around in one of the provided positions using the combination of pipe end (1) and press fitting (2).

The lower press jaw elements (6, 10̸) have between them a closing gap (46) in the positions shown in Figures (1) and (2). In the figures (1) it is so large that the press ring (5) can be put over the press fitting (2) and pipe end (1). The free ends of the pressing jaw elements (6, 10̸) delimiting the closing gap (46) carry hinge pins (47, 48), a coupling lug (49, 50̸) being suspended from each hinge pin (47, 48). The shape of the coupling straps (49, 50̸) and their connection with the hinge pins (47, 48) result in particular from the sectional view according to Figures (3) and (4).

The free ends of the coupling tabs (49, 50̸) have through openings (51, 52). In the through hole (51) of the coupling bracket (49), a coupling pin (53) is inserted axially. It has a first bolt section (54) with which it passes through the through hole (51). One end of the first bolt section (54) is connected to a hand lever (55). A second pin section (56) is formed on the other end of the first pin section (54), the axis of which is offset by an eccentricity (57) with respect to the axis of the first pin section (54). The second pin section (56) fits into the through hole (52) ) of the other coupling plate (50̸) The coupling plates (49, 50̸) together with the coupling bolt (53) form a coupling element for the temporary connection of the ends of the pressing ring (5) before the actual pressing process.

As can be seen from the illustration in FIG. (6), the press jaws (16, 17, 18, 19, 20̸) are not only axially guided by the clamping devices (34, 35, 36, 37, 38), but also by the other side of the press jaw carrier (11, 12, 13, 14, 15) screwed on guide plates (62). The press jaws (16, 17, 18, 19, 20̸) themselves have an asymmetrical cross-sectional contour. They have an annular groove (63), the pressing grooves (63) of all pressing jaws (16, 17, 18, 19, 20̸) complementing one another to form a continuous circumferential annular groove. The cross section of the press groove (63) is adapted to the annular bead (3), which carries a sealing ring (64) on the inside.

A pressing web (65) runs along one side of the annular groove (63). It also complements the press bars of the other press jaws (16, 17, 18 19, 20̸) to form a continuous circumferential press bar. The press web (65) is intended to dig into the material of the press fitting (2) during the pressing process and also to dig in to deform the pipe end (1). On the other side of the annular groove (63), such a press bar is not provided.

For a pressing process, the opened press ring (5) is first placed over the pipe end (1) and the press fitting (2), as can be seen from the figures (1) and (6). When the press ring (5) is seated on the pipe end (1) or press fitting (2), the two lower press jaw elements (6, 10̸) are pivoted towards each other and onto the pipe end (1), so that they correspond to those shown in Figure (2 ) assume the position shown. The coupling straps (49, 50̸), which then still hang down and are shown in dash-dot lines in this position in FIG. (2), are then pivoted in the directions of arrows C and D with respect to one another. The coupling bolt (53) is in such a position that its second bolt section (56) does not protrude through the through bore (51), which is indicated in FIG. (3) by the position of the hand lever (55) shown in dotted lines.

The coupling lugs (49, 50̸) are pivoted into a position where they overlap and the through holes (51, 52) merge into one another. Of the Coupling bolt (53) and thus the hand lever (55) are in such a position that the second bolt section (56) is offset in the direction of the other coupling plate (50̸) and therefore easily in the through bore (52) by axial displacement of the Grip the coupling pin (53) so that both coupling brackets (49, 50̸) can couple. In this position, the press ring (5) still has a certain amount of slack.

The hand lever (55) is then pivoted from the position shown in solid lines in Figure (2) to the dash-dotted position in the direction of arrow E by 180 °. As a result, the second pin section (56) executes an eccentric movement and thereby shortens the distance between the two hinge pins (47, 48) by twice the eccentricity (57). This is clear from the comparison of Figures (3) and (4), with Figure (4) showing the pivoted position. As a result, a circumferential force is applied to the press ring (5) via which the press jaws (16, 17, 18, 19, 20̸) press onto the press fitting (2) with a certain radial preload. The press ring (5) then has a seat that is difficult or impossible to turn. This effect is supported by the clamping rams (39, 40̸, 41, 42, 43), which then rest against the pipe end (1) with a likewise radially directed prestress.

Now the actual pressing process can begin. For this purpose, a locking device (not shown) belonging to the pressing tool (4) is used, as is known schematically from Figure (7) of EP-A-0̸ 451 80̸6. This locking device has two pincer-shaped lever arms with which the locking device can be attached to the hinge pins (47, 48). They cover gaps (58, 59) or (60̸, 61) and then lay on the outside of the hinge pin (47, 48). The pliers-like lever arms are then moved together by means of a hydraulic motor belonging to the locking device, so that the hinge pins (47, 48) approach each other. This has the consequence that the press ring (5) contracts and thereby the press fitting (2) and the pipe end (1) are radially compressed, the press web (65) digging into the material of the press fitting (2) a little and the ring bead (3) is pressed against the pipe end (1) in such a way that the sealing ring (64) is pressed onto the pipe end (1) with the radial force required for a good seal. The press jaws (16, 17, 18, 19, 20̸) move automatically in the circumferential direction to adapt to this process until the end faces of the press jaws (16, 17, 18, 19, 20̸) come into contact with each other. At the same time, the coupling tabs (49, 50̸) dodge to the outside, so they do not hinder the pressing process. After completion of the pressing process, the pressing ring (5) assumes the position shown in FIG. (5). After axial displacement of the coupling pin (53) in such a way that the second pin section (56) moves out of the through hole (52), the press ring (5) can be removed again and used for further pressing processes.

Claims (3)

1. Press tool for compressing tubular interengaged workpieces (1, 2), in particular a tube end (1) and a press fitting (2) pushed thereon, comprising a plurality of press-jaw elements (6, 7, 8, 9, 10) with press jaws (16, 17, 18, 19, 20) having an internally moulded respective peripherally extending press groove (63) which comprises a press web (65) along only one side, characterized in that towards the other side a gauge (44) is arranged which fits over the inserted workpiece (1), however, not over the pushed on workpiece (2).
2. Press tool according to Claim 1, characterized in that the gauge (44) is shaped like a mouth.
3. Press tool according to Claim 1 or 2, characterized in that the gauge is composed of a sheet-metal portion which is attached to one of the press-jaw elements (8).

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