EP1360019B1 - Expansion tool for expanding tube ends and pressing device comprising such an expansion tool - Google Patents

Abstract

The invention relates to an expansion tool for expanding tube ends. The expansion tool has an expansion mandrel and a counter-support, said expansion mandrel consisting of a tow-bar and an elastic rubber expansion element surrounding it. The counter-support supports the expansion element on the base extremity and radially surrounds it at a distance. In order to improve an expansion tool of the above-described kind, the tow-bar is anchored in a bolt fastening element and the counter-support can be impinged upon via a pressure bar element that projects beyond the bolt fastening element in the longitudinal direction of the tow-bar.

Description

The invention relates according to the preamble of claim 1, a widening tool for expanding Pipe ends, wherein the expansion tool a Aufdddorn and a Contra-holder, wherein further the expanding mandrel of a pull rod and a surrounding, elastic rubber expansion element consists and the Counterholder the expansion element supports the foot and radially spaced surrounds.

Such expansion tools for expanding pipe ends are known. The pipe end to be widened is in this case in an annular space between the expansion element and the counter-holder, which is followed by Movement of the drawbar towards the foot, the widening element abstützenden counter holder bottom the expander is upset what a Expansion of the pipe end has the consequence.

A generic expansion tool, for example, from the PATENT ABSTRACT OF JAPAN vol. 014, no. 147 (M-0952), March 20, 1990 (1990-03-20) & JP 02 011233 A (SEKISUI CHEM CO LTD), January 16, 1990 (1990-01-16). In which Known expansion tool is the pull rod on a piston of a Cylinder / piston unit anchored directly. Such a widening tool can not be attached to conventional hydraulic devices, in particular pressing devices become.

With regard to the prior art described above, a technical problem of the invention seen in a Aufweitwerkzeug the to further develop the type in question in an advantageous manner.

This problem is initially and essentially solved in the subject matter of claim 1, wherein it is based on that the drawbar is anchored in a bolt fastener and that the counter-holder can be acted upon via a push rod element, in the longitudinal direction of the drawbar to the bolt fastener protrudes. According to this advantageous embodiment, the expansion tool according to the invention can be attached in the simplest manner to conventional hydraulic devices, in particular pressing devices which act on the expanding tool via rollers, in particular on the push rod element. The expander according to the invention is formed so that is displaced by pressurizing the push rod elements, eg. Via the rollers of a pressing device, the counter-holder relative to the, anchored in the bolt fastener tie rod, which is the expansion of the tie rod and the foot against the Counter support supporting rubber expansion element causes. The expansion tool is connected via the bolt-fastening element with the device acting on the push rod element rigidly, but preferably interchangeable connected. For this purpose, it is provided that the bolt fastening element has a transverse to the axial direction of the drawbar bolt receiving bore. Thus, the expansion tool according to the invention in the simplest manner by means of a bolt connection with the pressure rod element acting on, as well as the bolt-fastener-holding pressing device by means of a bolt or the like is connectable. It is further proposed that the push rod element is mounted in the anvil. Thus, for example, a screw connection can be provided here. However, it is also conceivable a welded joint. It is also proposed that the push rod element passes through the bolt fastener. Accordingly, the pressurization of the push rod element takes place in the direction of actuation of the same upstream of the attachment region of the expansion tool, wherein the push rod element is freely displaceable in its Längsachsrichtung in the fastener. Preferred is an embodiment in which the push rod element is formed plunger-like. Accordingly, the push rod element is not attached to the counter-holder, but acts only adjacent thereto, wherein a pressurization of the push rod element is transmitted via the pressing device to be arranged on the counter-holder. The provision of Aufweitwerkzeuges takes place automatically on the return properties des.elastischen Aufweitelementes, which at one end on the anchored pull rod supporting the anvil and hereby the only adjacent plunger moves back to the starting position. Particularly advantageous, in particular with regard to a uniform force transmission proves to be an embodiment in which more than two push rod elements or plunger are provided. Thus, an embodiment is particularly preferred in which four arranged in a cross section through the push rod elements in a rectangle push rod elements or plunger pass through the bolt fastener and act on the anvil. In a Aufweitwerkzeug of the type in question, in which the counter-holder is cup-shaped, it is further provided that in the bottom of the pot, a step is formed, which receives a foot portion of the expansion element. As a result of this configuration, critical bulges in the area of the expansion process are avoided in the foot region of the expansion element. In addition, the step on the upper side serves as a stop for a tube to be expanded, which, in conjunction with the step formed on the inside, has the advantageous effect of achieving a uniform expansion extending into the end of the tube to be expanded. For different sized tubes different expansion tools may be provided, which is connectable to the respective bolt-fastener with the pressing device or the like. Alternatively, it is proposed that a screw-in adapter part is provided in the bolt fastening element for fastening the pull rod, for adaptation to different tie rod diameters. This embodiment proves to be advantageous in particular in connection with the arrangement of plungers resting only on the counterholder. Thus, in the simplest way the same bolt-fastener different tie rods and backstops can be assigned. In a further development of the subject invention, it is provided that in the direction of loading in front of the counter-holder a pressure plate is arranged, on which the push rod elements act and that between the pressure plate and the counter-holder a force-limiting device is arranged. In this case, the force-limiting device preferably consists of a plastic part, wherein the plastic part has a higher rigidity than the expansion element. This expansion element can also be a flexible plastic, which has a very high hardness of, for example, 90 to 100 Shore, preferably about 95 Shore. This is preferably a polyurethane plastic, over which pressures up to about 200 bar can be generated. In order to counteract critical formations in the area of the free end of the expander element facing away from the counterholder base, it is provided in an embodiment of the subject invention that downstream of the expander element, but nevertheless also caught by the drawbar, an expander-transition element is arranged in the loading direction. The latter preferably consists of a stop compression-limited plastic part.
As a result of this configuration, possible formations in the end region of the expansion element, which can be set at high pressures, are limited by a resulting bead of the expansion transition element. In this regard, it is further provided that the stop compression by a, against the expansion element limiting stop disc movable stop sleeve, further wherein the stop sleeve has a, acted upon by a Zugstangenkopf sleeve bottom, which merges into a pipe section surrounding the pull rod. Consequently, the widening transition element is sandwiched between two sleeve elements, which sleeve elements have collapsed at a given compression and so do not allow further compression of the widening transition element. In order to ensure an exact expansion of the pipe end, it is provided in a development of the subject invention that a die element is received within the counter-holder. The latter forms in the course of the expansion process, a negative mold, in which the pipe end is pressed by means of the rubber expansion element. This also prevents the elastomer element flows in the course of expansion over the collar at the end of the drawbar out in a gap between the collar and pipe end and this uncontrolled further expansion of the pipe end is effected. The die element can be shaped in the form of half-shells to be screwed manually, which support the end region of the pipe to be expanded. By contrast, a configuration in which the die element divided in the longitudinal direction is composed of a plurality of partial dies is preferred, for example, four quarter shells forming a 90 ° circle segment in cross-section. The received in the anvil die element or the received sub-matrices are displaceable relative to the anvil in the axial direction. In this regard, it is proposed that the die element engages under the elastic rubber expansion element, wherein it is preferably further provided that the die element is caught with radially aligned collar in the region of the drawbar between the rubber expansion element and a pressure spring supported in the region of a counter-holder bottom. Particularly advantageous is that a sub-die in the course of compression from a removal position for the pipe end to be expanded by axial displacement in a Verpressstellung while reducing the radial distance to the drawbar is displaced. According to this embodiment, the sub-matrices of the die element in the course of the expansion process are displaced radially in the direction of the tube end to be expanded, after which partial axial sections of the sub-matrices rest on the outer wall of the tube to be expanded supported by the counter-holder. As a result, no annular gap can arise between the tie rod and tube, in which the elastomeric material of the expansion element can flow in an uncontrolled manner. The widening of the pipe end is clearly defined in its geometry, in particular in its axial extent. With regard to the radial displacement of the sub-matrices in the course of the expansion process is provided in an advantageous development of the subject invention that on the counter holder inside a guide bevel is formed, which cooperates with a guide projection of the die element. In order to secure an axially parallel displacement of the die element or its sub-matrices, it can further be provided that two mutually distanced guide bevels are arranged in the axial direction at different radial distances from the drawbar.

Another embodiment of The invention further relates to a pressing device with a widening tool for expanding pipe ends according to claim 1, wherein the pull rod with the Pressing device is firmly connected while the anvil is acted upon by a push rod element. The latter is used for actuation of the pressing device relative to Tow bar shifted. Furthermore, it is envisaged that anchored the drawbar in a bolt fastener is, what latter the attachment of the expansion tool serves on the pressing device. According to that is the pull rod over the fastener rigid with connected to the pressing device. It is also envisaged that the push rod element in the longitudinal direction of the pull rod extends beyond the bolt fastener. In A preferred embodiment provides that the bolt fastener a transversely to the axial direction the drawbar extending bolt-receiving bore has, for bolt connection of the expansion tool with the pressing device, wherein it is further preferred that the push rod element the bolt fastener interspersed. According to this embodiment, the push rod element in the longitudinal direction of the drawbar free in the bolt fastener displaced. Further advantageous, in particular with regard to an improved Power transmission, it turns out, if more than two push rod elements are provided. So be preferably arranged four push rod elements, which the bolt fastener outside of the bolt receiving bore prevail and more preferably in one Cross section through the push rod elements of a rectangular shape are arranged adjusted. The push rod element can be further connected to the counter-holder be, for example, screw or welding connected. Preferred is an embodiment in which the Push rod element as a merely abutting, with the plunger unconnected tappet formed is. Finally, it is suggested that the pressing device acts on the rams via rollers.

Fig. 1

eine Ansichtsdarstellung eines Pressgerätes mit einem angeordneten, erfindungsgemäßen Aufweitwerkzeug in einer Grundstellung;

Fig. 2

eine Einzeldarstellung des Aufweitwerkzeuges in Draufsicht;

Fig. 3

eine Seitenansicht des Aufweitwerkzeuges;

Fig. 4

den Schnitt gemäß der Linie IV-IV in Fig. 2, die Grundstellung des Aufweitwerkzeuges betreffend;

Fig. 5

eine Schnittdarstellung gemäß Fig. 4, jedoch die Arbeitsstellung betreffend;

Fig. 6

eine der Fig. 2 entsprechende Darstellung, jedoch eine zweite Ausführungsform des Aufweitwerkzeuges betreffend;

Fig. 7

eine Seitenansicht hierzu;

Fig. 8

den Schnitt gemäß der Linie VIII-VIII in Fig. 6, die Grundstellung betreffend;

Fig. 9

eine der Fig. 8 entsprechende Schnittdarstellung, jedoch die Arbeitsstellung betreffend;

Fig. 10

eine Herausvergrößerung des Bereiches X-X in Fig. 9;

Fig. 11

eine perspektivische Explosionsdarstellung des Aufweitwerkzeuges der zweiten Ausführungsform;

Fig. 12

das Aufweitwerkzeug in Perspektive anordbar an ein hydraulisches Pressgerät;

Fig. 13

eine weitere perspektivische Darstellung, nach Anordnung des Aufweitwerkzeuges an ein Pressgerät;

Fig. 14

eine partiell geschnittene, perspektivische Darstellung eines Aufweitwerkzeuges in einer dritten Ausführungsform, eine unbelastete Grundstellung betreffend;

Fig. 15

einen Längsschnitt durch das Aufweitwerkzeug gemäß Fig. 14;

Fig. 16

eine perspektivische Explosionsdarstellung des Aufweitwerkzeuges;

Fig. 17

eine der Fig. 14 entsprechende Darstellung, die Verpressstellung betreffend;

Fig. 18

den Längsschnitt gemäß Fig. 15, jedoch die Stellung gemäß Fig. 17 betreffend;

Fig. 19

eine weitere der Fig. 14 entsprechende Darstellung nach einem Aufweiten eines Rohrendes;

Fig. 20

den Längsschnitt zu Fig. 19.

The invention with reference to the accompanying drawings, which illustrates only three embodiments, explained in more detail. It shows:

Fig. 1

a view of a pressing device with an arranged, expansion tool according to the invention in a basic position;

Fig. 2

a detailed view of the expansion tool in plan view;

Fig. 3

a side view of the expansion tool;

Fig. 4

the section along the line IV-IV in Figure 2, concerning the basic position of the expansion tool.

Fig. 5

a sectional view of Figure 4, but concerning the working position.

Fig. 6

a representation corresponding to FIG. 2, but relating to a second embodiment of the expansion tool;

Fig. 7

a side view of this;

Fig. 8

the section along the line VIII-VIII in Figure 6, concerning the basic position;

Fig. 9

one of Figure 8 corresponding sectional view, but concerning the working position.

Fig. 10

an enlargement of the area XX in Fig. 9;

Fig. 11

an exploded perspective view of the expansion tool of the second embodiment;

Fig. 12

the expansion tool in perspective to a hydraulic pressing device;

Fig. 13

a further perspective view, after arrangement of the expansion tool to a pressing device;

Fig. 14

a partially sectioned, perspective view of a Aufweitwerkzeuges in a third embodiment relating to an unloaded basic position;

Fig. 15

a longitudinal section through the expansion tool of FIG. 14;

Fig. 16

an exploded perspective view of the expansion tool;

Fig. 17

a representation corresponding to FIG. 14, concerning the injection position;

Fig. 18

the longitudinal section of FIG. 15, but the position of FIG. 17 concerning;

Fig. 19

another illustration corresponding to FIG 14 after an expansion of a pipe end.

Fig. 20

the longitudinal section to Fig. 19.

Shown and described is first with reference to Fig. 1, a widening tool 1 for connection to a hydraulic press 2. The latter has a bolt fixed part 3 for fixing the expansion tool. 1 In addition, it has a hydraulic over a piston 4 relative to the bolt fixed part 3 displaceable Movement part 5, which in the embodiment shown in a cross section substantially U-shaped and two juxtaposed Traversing rollers 6 rotatably supports.

The expansion tool 1 serves to expand pipe ends 7, including the expansion tool 1 an expanding mandrel 8 as well having a counter-holder 9.

In a first embodiment according to the illustrations in FIGS. 1 to 5, the expanding mandrel 8 essentially exists from a pull rod 10 and a surrounding, elastic expansion element 11, which latter preferably a polyurethane plastic. The drawbar 11 has one end, the expansion element 11th supporting Zugstangenkopf 12, whose diameter that of the expansion element 11 in the unloaded position corresponds to FIG. 4.

The surrounding the Aufweitdorn 8 backstop 9 is cup-shaped formed, with one in the direction of the tie-rod headboard pointing, annular in cross-section remaining free receiving opening 13 which radially is limited inside by the expansion element 11 and radially outwardly through the Gegenhalterwandung 14. The Counterholder 9 is relative to the pull rod 11 in the longitudinal direction same mobile.

The pull rod head 12 facing away from the bottom of the pot 15 Counter-holder 9 forms on the inside a step 16, which a foot area 17 of the expander 11th receives, wherein the diameter of the step 16 the expander diameter is adjusted ..

The limited by the Gegenhalterwandung 14 pot bottom 15 serves as a stop for the pipe end to be expanded 7. The marginal edge in the transition area between the bottom of the pot 15 and stage 16 is provided with a phase 18.

The pull rod 10 passes through the anvil 9 in the area a correspondingly adapted. Bore 19 of Pot bottom 15 and is the end, the tie rod end 12th opposite, in a bolt fastener 20 anchored. The latter is in the illustrated embodiment formed cuboid and facing the Anchoring the tie rod 10 a threaded hole 21st into which an end-side threaded portion 22 of the Pull rod 10 engages.

This bolt fastener 20 is used for mounting the Aufweitwerkzeuges 1 on the pressing device 2, including the Bolt fastener one transverse to the axial direction the pull rod 10 extending bolt-receiving bore 23rd having. By the latter enters the bolt fixed part. 3 of the pressing device 2.

Furthermore, the bolt fastening element 20 on both sides of the bolt receiving bore 23 in each case two superimposed, in the axial direction of the drawbar 10 aligned guide holes 24, to the passage of push rod elements 25 in the form of plungers 26. The latter project on both sides of the bolt fastening element 20 beyond this, with the, respectively with a locking ring 27 provided one ends 28 in the Area of the pot bottom 15 adjacent to the anvil 9 apply this. The these ends 28 facing away Ends 29 are with radial thickenings 30th provided, against which the traversing rollers 6 of the pressing device 2 to apply pressure.

For expanding a introduced into the receiving opening 13 Pipe end 7, the pressing device 2 is operated, which via the piston 4 a forward displacement of the traction rollers 6 causes. The latter act on the ram 26, which is a displacement of the counter 9 relative to the pull rod 10 has in the direction of rotation r result. In the course of this counter-displacement is the expansion element 11, which between the bottom of the pot 15 and the Stage 16 and the anchored tie rod end 12 taken is compressed, what a radial expansion of the same and accompanied by a radial expansion of the pipe end. 7 has according to FIG. 5 result. This radial expansion is stop limited by the Gegenhalterwandung 14th

After exceeding a predetermined force of the drives Piston 4 of the pressing device 2 automatically in its initial position as shown in FIG. 1, whereby the rear Support the plunger 26 is released. The Expansion tool 1 arises, due to the elastic Properties of expansion element 11, automatic in the starting position, after which the expanded Pipe end 7 of the receiving opening 13 of the counter-holder 9 is removable.

FIGS. 6 to 10 show a second embodiment a Aufweitwerkzeuges 1, which as in the previous described embodiment by a pressing device 2 can be acted upon. Here is the bolt fastener 20 is the same as the first embodiment, wherein for the arrangement of a tie rod 10th for pipe ends 7 smaller diameter a screw-in adapter part 31 screwed into the threaded hole 21 is. This allows the attachment of tie rods 10th with different diameters on one and the same Bolt fastener 20. This is only each the appropriate screw-adapter part 31 in the Threaded hole 21 to screw.

This screw-adapter part 31 in turn has a Threaded hole 32 for receiving the end-side threaded portion 22 of the drawbar 10 on, which latter is secured by a lock nut 33.

The counter-holder 9 of this second embodiment has a arranged in the direction of application r before this Pressure plate 34 on. Between this and the counter-holder 9 is a, consisting of a plastic part Force limiting device 35 is arranged. This Plastic part has a higher rigidity than the expansion element 11.

The bolt fastener 20 passing through Push rod element 25 and plunger 26 act in this embodiment, the pressure plate 34 on the Counterholder 9 opposite side.

Furthermore, in this second embodiment downstream in the direction of supply r to the Expander element 11, however caught anyway by the tie rod 10 a widening transition element 36 arranged. The latter consists of a stop-compression-limited Plastic part 37, which is caught between a stop plate 38 and a Stop sleeve 39, whose, the pull rod 10 surrounding Pipe section 40 which is annular in cross-section plastic part 37 carries.

The stop disc 38 limits the expander 11th in which, the pot bottom 15 of the counter-holder 9 facing away End region and is displaceable relative to the pull rod 10.

The stop sleeve 39 is supported against the Zugstangenkopf 12 off.

The measured in the longitudinal extent of the drawbar 10 Width of the plastic part 37 is chosen larger than the length measured in the same direction of the Pipe section 40, bringing between the free pipe section end and the stopper plate 38 a between the plastic part 37 and the tie rod 10 extending free annulus remains.

To a introduced into the Aufweitdorn 8 pipe end. 7 expand, are also in.diesem embodiment the push rod elements 25 and plunger 26 via traction rollers 6 acted in the direction of movement r, which is a Displacement of the counter-holder 9 together with the pressure plate 34 and the force limiting device 35 in the direction of movement r against the anchored pull rod 10 for Episode has. The initiated force is through the plastic part between the counter-holder 9 and pressure plate 34 limited.

In the course of this shift is also the expansion element 11 compressed, this under radial expansion thereof. As a result, the pipe end 7 is stop-limited expanded against the Gegenhalterwandung 14.

In addition, the force introduced via the plunger 26 causes an axial displacement of, the expander 11 end limiting pressure stopper plate 38 in the direction on the stop sleeve 39 until the stopper plate 38th stop limited against the pipe section 40 of the stop sleeve 39 occurs. This is a compression between stop disk 38 and stop sleeve 39 caught plastic part 37.

As a result of this embodiment, an optional occurring formation 41 in, the pull rod 12th facing end portion of the expander 11, which Forming at high pressures, by a resulting bead 42 of the widening transition element 36 limited.

In the foot area 17 is a critical bulge of the Expansion element 11 -as already in the first embodiment through the enclosure in stage 16 counteracted.

Figs. 14 to 20 show a third embodiment the Aufweitwerkzeuges 1, wherein according to the second Embodiment of the counter-holder 9 in a loading direction r in front of this arranged pressure plate 34 has. Again, between the pressure plate 34th and the counter-holder 9, a force-limiting device 35 arranged, which has a higher rigidity as the expansion element 11.

Within the counter-holder 9 is in this embodiment a die element 43 was added, which as shown above the open end of the cup-shaped Counter-holder 9 protrudes in the axial direction.

The die element 43 is divided in the longitudinal direction and is made up of four sector-like cross sections Submatrices 44.

The die element 43 or its sub-dies 44 are the expansion area, d. H. the tube 7 to be expanded facing according to the desired Aufweitgeometrie formed. As a result, each sub-die has 44 an expansion section 49 and an abutment section 50, wherein the transition between Aufweitabschnitt 49 and Anlageabschnitt 50 at an acute angle of about 30 ° runs to the longitudinal axis.

Wandungsinnenseitig is the counter-holder 9 with two in Axial direction to each other distanced guide slopes 45, 46 provided, which at an angle of approximately 45 ° to Longitudinal axis of the expansion tool 1 run. in this connection is the bottom of the pot 15 facing guide slope 45th with a smaller radial distance to the drawbar 10th as the pot bottom 15 lying away guide slope 46 arranged.

The die element 43 or the sub-dies 44 have in the area encompassed by the counter-holder 9 outer wall outer wall shaped according to the guide slopes 45, 46 and positioned guide projections 47, 48 on. In an unloaded basic position according to Figs. 14 and 15 are the guide projections 47, 48 of the Part matrices 44 on the guide slopes 45, 46 of the Counterholder 9 on.

Each sub-die 44 also has, in the pot bottom 15th of the counter-holder 9 facing end after a radially inward toward the drawbar 10 projecting Carrying section 51, which with the interposition of 10 freely displaceable in the axial direction on the pull rod Slices 52 in the axial direction on the one hand by the Expander 11 and on the other hand by a on the pot bottom 15 supporting compression spring 53 acted upon becomes.

The arrangement of the sub-matrices 44 in the starting position as shown in FIGS. 14 and 15 is chosen so that the facing side surfaces of the sub-matrices 44 spaced apart a gap between to stay. Furthermore, also the radially inner End edge of the driving portions 51 to the pull rod 10th spaced.

To enter the free annulus between tie rod 10 and to widen the tube end 7 introduced into the sub-matrices 44, are also in this embodiment, the Push rod elements 25 and plunger 26 in the direction of movement r acted upon. Accordingly, a Displacement of the counter-holder 9 via the pressure plate 34th and the force limiting device 35 against the anchored pull rod 10.

In the course of this shift will be on the takeaway sections 51 of the entrained via the counter-holder 9 Sub-matrices 44, the expansion element 11 compressed, wherein this entrainment of the Teilmatrizen 44 up to a Point takes place in which the on the driving sections 51 acting force of the expansion element 11 is greater than in the opposite direction to the driving sections 51 acting force of the compression spring 53. This has a relative displacement of the sub-matrices 44 opposite the anvil 9 result, with the guide projections over 47, 48 and the guide slopes 45, 46 an axis-parallel radial displacement of the sub-matrices 44 is effected in the direction of the tie rod 10. This shift of the sub-matrices 44 radially inward is stop limited by creating the plant sections 50 on the outer wall of the pipe to be expanded and / or by applying the mutually assigning Side surfaces of the sub-matrices 44.

In the course of further advancement of the counter-holder 9 the expansion element 11 is further compressed. according to this will be the pipe end 7 in the contact sections 50th the sub-matrices 44 pressed and expanded.

As in particular from the sectional view in FIG. 18 to recognize the sub-matrices 44 are based radially outwards at the plan, between the guide slopes 45 and 46 formed pot wall of the counter-holder 9, so that a radial deflection of the pipe end 7 outside the desired expansion zone is counteracted. As a result, a controlled, by shaping the sub-matrices 44 predefined expansion of the Pipe end 7 allows.

Is after widening the pressing device 2 automatically is returned to its original position is the counter-holder 9 via the driving portions 51 of Part matrices 44, due to the elastic recovery properties of the expansion element 11, again in the initial situation back process. The sub-matrices 44 are hereafter still in their after radially inwardly displaced position, but without radially outer support through the pot wall of the Counterholder 9. The tube end 7 can hereafter in the simplest Way in the axial direction from the expansion tool 1, this under relocation of the sub-matrices 44 radially outward, due to the between Aufweitabschnitten 49 and abutment sections 50 formed bevels, which also in the widened Adjust pipe end 7. It turns hereafter the starting position shown in FIGS. 14 and 15 of the expansion tool 1 on.

Advantageously, the expansion tool described is 1 can be arranged on a conventional pressing device 2.

Claims (30)

1. Expansion tool (1) for expanding tube ends (7), the expansion tool (1) having an expansion mandrel (8) and a counter-support (9), and, furthermore, the expansion mandrel (8) comprising a pull rod (10) and an elastic rubber expansion element (11) which surrounds the latter, and the counter-support (9) supporting the expansion element (11) at the foot end and surrounding it radially at a spacing therefrom, characterized in that the pull rod (10) is anchored in a bolt-fastening element (20), and in that the counter-support (9) can be acted upon by a push-rod element (25), which extends beyond the bolt-fastening element (20) in the longitudinal direction of the pull rod (10).
2. Expansion tool according to claim 1, characterized in that the bolt-fastening element (20) has a bolt-accommodating bore (23) running transversely to the axial direction of the pull rod (10).
3. Expansion tool according to one of the preceding claims, characterized in that the push-rod element (25) is secured in the counter-support (9).
4. Expansion tool according to one of the preceding claims, characterized in that the push-rod element (25) passes through the bolt-fastening element (20).
5. Expansion tool according to one of the preceding claims, characterized in that the push-rod element (25) is formed in the manner of a ram.
6. Expansion tool according to one of the preceding claims, characterized in that more than two push-rod elements (25) are provided.
7. Expansion tool according to one of the preceding claims, the counter-support (9) being in cup form, characterized in that formed on the inside of the cup base (15) is a step (16) which accommodates a foot region (17) of the expansion element (11).
8. Expansion tool according to claim 7, characterized in that the step (16), on the upper side, serves as a stop for a tube which is to be expanded.
9. Expansion tool according to one of the preceding claims, characterized in that, for the purpose of securing the pull rod (10), a screw-in adapter part (31) is provided in the bolt-fastening element (20), for adaptation to different pull-rod diameters.
10. Expansion tool according to one of the preceding claims, characterized in that disposed upstream of the counter-support (9), as seen in the direction of action (r), is a pressure plate (34), on which the push-rod elements (25) act, and in that a force-limiting device (35) is disposed between the pressure plate (34) and the counter-support (9).
11. Expansion tool according to claim 10, characterized in that the force-limiting device (35) comprises a plastics-material component.
12. Expansion tool according to claim 11, characterized in that the plastics-material component has a higher stiffness than the expansion element (11).
13. Expansion tool according to one of the preceding claims, characterized in that an expansion transition element (36) is disposed downstream of the expansion element (11), as seen in the direction of action (r), but is nevertheless also held captive by the pull rod (10).
14. Expansion tool according to claim 13, characterized in that the expansion transition element (36) comprises a plastics-material component (37) with stop-limited compression.
15. Expansion tool according to claim 14, characterized in that the stop-limited compression comprises by a stop sleeve (39) which can be moved against stop ring (38) which bounds the expansion element (11).
16. Expansion tool according to claim 15, characterized in that the stop sleeve (39) has a sleeve base which is acted upon by a pull-rod head (12) and merges into a tubular portion (40) which surrounds the pull rod (10).
17. Expansion tool according to one of the preceding claims, characterized in that a female-die element (43) is accommodated within the counter-support (9).
18. Expansion tool according to claim 17, characterized in that the longitudinally split female-die element (43) is made up of a plurality of female sub-dies (44).
19. Expansion tool according to one of the claims 17 or 18, characterized in that the female-die element (43) engages beneath the elastic rubber expansion element (11).
20. Expansion tool according to one of the claims 18 or 19, characterized in that, during pressing, a female sub-die (44) can be displaced axially from a removal position for the tube end (7) which is to be expanded into a pressing position, the radial distance from the pull rod (10) being reduced in the process.
21. Expansion tool according to one of the claims 17 or 20, characterized in that formed on the inside of the counter-support (9) is a guide slope (45, 46) which interacts with a guide protrusion (47, 48) of the female-die element (33).
22. Expansion tool according to claim 21, characterized in that, in the axial direction two spaced-apart guide slopes (45,46) are disposed at different radial spacing from the pull rod (10).
23. Pressing device (2) comprising an expansion tool (1) for expanding tube ends (7) according to one of the preceding claims, wherein the pull rod (10) is fixedly connected to the pressing device (2).
24. Pressing device according to claim 23, characterized in that the pull rod (10) is anchored in a bolt-fastening element (20).
25. Pressing device according to claim 24, characterized in that the push-rod element (25) projects beyond the bolt-fastening element (20) in the longitudinal direction of the pull rod (10).
26. Pressing device according to one of the claims 24 or 25, characterized in that the bolt-fastening element (20) has a bolt-accommodating bore (23) running transversely to the axial direction of the pull rod (10).
27. Pressing device according to one of the claims 24 to 26, characterized in that the push-rod element (25) passes through the bolt-fastening element (20).
28. Pressing device according to one of the claims 23 to 27, characterized in that more than two push-rod elements (25) are provided.
29. Pressing device according to one of claims 23 to 28, characterized in that the push-rod element (25) is formed as a ram (26) which merely butts against the counter-support (9), but is not connected thereto.
30. Pressing device according to claim 29, characterized in that the pressing device (2) acts on the rams (26) via rollers (6).

Images