EP0771615A1 - Crimping device for radially crimping tube connections - Google Patents

Abstract

The tool incorporates two base jaws (2, 3) in the form of lever arms (7, 9; 8, 10) provided with cutouts (4, 5) for changeable jaw inserts (20, 21), whose inner surfaces (22, 23) are shaped to produce a required profile on the respective pipe or hose connector. At least two slide elements (24) per each jaw insert (20, 21) are located between the base jaws (2, 3) and the jaw inserts. The slide surfaces of the elements(24) are parallel to the axis of the pipe or hose connector, and are arranged so that the inserts (20, 21) can be slid along them into and out of the base jaws.

Description

The invention relates to a pressing device for the radial pressing of line connectors, which have an axis (AA), with two mutually movable pliers-shaped base jaws surrounding a pliers jaw, which are designed as lever arms and have recesses in which on both sides of an uninterrupted dividing joint are secured in a semi-ring-shaped manner against rotation , interchangeable jaw inserts are arranged, the inner surfaces of which are matched to the press profile to be produced on the line connectors.

Such pressing devices are used to connect pipe or hose sections to one another or to fittings. Here, a metal sleeve with the interposition of two sealing rings can be pressed onto the ends of two pipelines, as described in DE-OS 27 25 280. Another possibility is to push one end of the line into the widened end of a second line and to press the widened end against the internal pipeline, as described in GB-OS 2 205 373.

Other options are to slide two hose ends onto a double-sided nipple and to fix the connection by pressing two steel rings together. The same technique can also be used when it comes to connecting a metal connector with a hose.

The so-called working or inner surfaces of such pressing devices can be designed very differently, they hang, among other things. on the line cross-section and thus on the outer dimensions of the line connector, but very well also on the maximum internal pressure for which the line is designed.

Manufacturers and users also have very different philosophies with regard to the geometric shape of the pre-pressed cable connection. Cable connections with shafts or beads are promoted, cable connections with circular or polygonal cross sections as well as mixed forms of such connections.

Such press devices usually therefore consist of a drive part, which can be designed as manually operated pliers, as an electric drive or as a hydraulic drive, and which is connected to a so-called press head, which has press jaws with a so-called pliers jaw, which has those work surfaces on the inside, which determine the geometric shape of the press connection. Such press heads are usually replaced as a whole. However, they are very heavy because they are made of steel, and the operator of such a pressing device then has to carry a large weight.

This considerably complicates working conditions on construction sites where there are no elevators in operation.

It has therefore already been concerned with arranging interchangeable jaw inserts in such press heads. Such a pressing device is described in the aforementioned DE-OS 27 25 280. This document discloses a generic pressing device, in which the security against rotation of the interchangeable jaw inserts is achieved by radially inwardly directed projections on the base jaws, these projections being arranged on both sides of the division joint. These firmly attached projections allow the jaw inserts to be pushed out parallel to the axis, but on the other hand prevent exact machining of the recesses provided in the base jaws, in which the jaw inserts are arranged. However, this precise machining of the recesses is necessary in order to produce precise seating surfaces for the jaw inserts.

Finally, it is also known from EP-PS 0 504 490 to fasten two of three interchangeable jaw inserts in two base jaws by means of radially aligned screws. In this case, replacing the jaw attachments is time-consuming and difficult on a construction site, especially since the fastening screws are lost or can become stiff.

Another type of pressing device, in which movable jaw inserts are arranged in base jaws, is known from EP-OS 0 451 806 and from GB-OS 2 205 373 already mentioned. In these cases, the possibility of movement of the jaw inserts in the circumferential direction serves to be able to maintain equal distances between the jaw inserts, which are sectors in the geometric sense. This mobility of the jaw inserts in turn requires appropriate guides, which make any replacement time-consuming and difficult:

In one embodiment according to EP-OS 0 451 806, two of three jaw inserts on opposite sides are with nose or Provide flange-shaped projections that overlap the base jaws. In the projections there are sliding blocks which are guided in arcuate sliding grooves in order to ensure the condition of equal distances between the individual sectors. In a further embodiment of the same document, two of three jaw inserts are guided in sector-shaped grooves in the base jaws, in which they can be rotated relative to one another in the circumferential direction by spring-loaded pins. In both exemplary embodiments, the expansion of the jaw inserts is difficult and is also not provided. An axial pushing out of the jaw inserts is not possible due to positive overlaps, and an expansion in the radial direction is only possible after the so-called press head has been completely disassembled because the base jaws cannot be opened far enough when assembled. It is therefore only intended to replace the so-called press heads.

In the pressing device according to GB-PS 2 205 373, the rotational mobility of the jaw inserts is ensured by axially parallel flange projections which engage in complementary annular grooves which are located in sector-shaped guide bodies which are screwed onto the base jaws on the end face. Axial removal of the jaw inserts is possible here, but only after unscrewing the guide bodies and after removing two L-shaped leaf springs that rotate the jaw inserts in their annular bearings. Both the disassembly and the reassembly are difficult and two-time in this case, especially since individual parts can also be lost in this case when converting such a pressing device. This known pressing device is also not provided for retrofitting, so that the so-called press head must be replaced as a whole if different press connections are to be made.

From DE 19 07 956 A1 a non-generic pressing device with a closed cylindrical housing is known, which at the same time serves as an outer wall for an annularly closed membrane. Six sector-shaped primary and secondary segments are moved through this membrane, for example in order to press line connections. Such a device can only be pushed axially onto a line, which makes it difficult, if not impossible, to process long and / or already laid pipelines. The sectors rest loosely on the membrane and are held in place by a) spreading them by compression springs, b) holding them in the housing by screwed-on end rings and c) engaging these end rings by means of projections. If inner or primary segments are used, these are each congruently connected to the outer or secondary segments either by a single cylindrical pin, referred to as dowel, or by a dovetail connection. In the former case, additional pressure springs distributed over the circumference are required to prevent uncontrolled movements. The inner segments can also only be replaced after dismantling at least one of the end rings, the clamping connection of the membrane also being released. Additional cylinder pins, which are arranged in the gaps between the inner segments, only serve to center the segments during the closing movement, because the membrane does not give the segments sufficient support. The entire arrangement is extremely complex to manufacture because of the large number of parts, because numerous machining processes have to be carried out and many tolerances have to be observed. Disassembly on a construction site is also problematic because parts can easily be lost.

Above all, however, the non-generic pressing devices described last are extremely complex and complicated and therefore also expensive to manufacture because they must have a large number of mating surfaces which also serve as sliding surfaces.

The invention is therefore based on the object of specifying a pressing device of the type described at the outset, which is distinguished by the simplest manufacture, robust construction and easy replacement of the jaw inserts without the use of tools and screw connections.

The object is achieved in the pressing device specified at the outset according to the invention in that between the pincer-shaped base jaws on the one hand and the half-ring-shaped jaw inserts on the other hand, at least two sliding bodies are used per jaw insert, the sliding surfaces of which run parallel to the axis AA and each with a part of their cross section protrude into the pincer-shaped base jaws and with another part of their cross-section into the jaw inserts such that the jaw inserts can be pushed out and in along the sliding bodies from the base jaws.

The use of the sliding bodies, which form an inseparable unit neither with the base jaws nor with the jaw inserts, ensures that the semi-cylindrical inner surfaces of the base jaws, which together form a full cylinder surface, and the semi-cylindrical outer surfaces of the jaw inserts, which together also form a full cylinder surface form, can be machined with rotary tolerances while maintaining close tolerances. The sliding bodies are only used during final assembly and are expediently connected to the base jaws, for example by gluing, pinning, screwing or caulking. The sliding bodies then serve as parallel guides for, for example, axially pushing the jaw inserts out of the base jaws.

With sufficient dimensioning and shaping of the sliding body, it is even possible in the borderline case to machine internal and external machining of the cylinder surfaces, the base jaws and the To dispense with jaw inserts, namely when the sliding bodies can absorb the entire pressing forces.

It is particularly advantageous if the sliding bodies are selected from the group of disc springs, insert keys, sliding springs or cylindrical pins and engage in essentially complementary recesses in the base jaws on the one hand and in the jaw inserts on the other.

These machine elements are standardized mass products that have a smooth and hardened surface and are available with the tightest tolerances. To produce the recesses, it is then only necessary to produce corresponding partial recesses in the base jaws on the one hand and in the jaw inserts on the other hand. Due to their finely ground and hardened surface, the machine elements mentioned are excellent parallel guides for the jaw inserts, so that noticeable wear could not be observed.

When using disc springs, it is particularly advantageous if their part-cylindrical part engages in part-cylindrical grooves in the base jaws and if their part bounded by parallel edges engages in complementary grooves of the jaw inserts.

If the pitch circle surfaces or the symmetry planes of the disc springs are aligned parallel to the parting line, it is possible with additional advantage to fix the disc springs with pins in the base jaws.

With all types of sliding bodies, it is alternatively possible to align the planes of symmetry of the sliding bodies radially to the axis AA, with particular advantage at an angle of 20 to 45 degrees to the dividing joint, preferably of 30 degrees.

It is also advantageous if the axes of four sliding bodies lie in the area of the corner points of a rectangle, the longest edges of which run parallel to the dividing joint and whose diagonals intersect in the axis A-A. In this way a tilt-free guidance of the jaw inserts in the recesses of the base jaws is guaranteed.

To axially fix the jaw inserts in the base jaws, latching elements of known design are used in a particularly advantageous manner, which can consist of latching balls and compression springs. For this purpose, there are recesses on the circumference of the jaw inserts into which the locking balls can engage.

Three exemplary embodiments of the subject matter of the invention are explained in more detail below with reference to FIGS. 1 to 8.

Figur 1

eine teilweise aufgebrochene Seitenansicht eines ersten Ausführungsbeispiels eines sogenannten Pressenkopfes,

Figur 2

einen Schnitt durch den Pressenkopf nach Figur 1 entlang der Linie III-III,

Figur 3

eine Seitenansicht eines zu den Figuren 1 und 2 gehörenden Backeneinsatzes in vergrößertem Maßstab,

Figur 4

eine Seitenansicht eines zweiten Ausführungsbeispiels in einer analogen Darstellung wie in Figur 1,

Figur 5

eine Seitenansicht eines zu Figur 4 gehörenden Backeneinsatzes in vergrößertem Maßstab,

Figur 6

eine Seitenansicht eines dritten Ausführungsbeispiels in einer analogen Darstellung wie in Figur 1,

Figur 7

eine Seitenansicht eines zu Figur 6 gehörenden Backeinsatzes in vergrößertem Maßstab, und

Figur 8

einen Radialschnitt durch den Gegenstand nach den Figuren 3, 5 und 7 entlang der Linien VIII-IIIV.

Show it:

Figure 1

a partially broken side view of a first embodiment of a so-called press head,

Figure 2

2 shows a section through the press head according to FIG. 1 along the line III-III,

Figure 3

2 shows a side view of a jaw insert belonging to FIGS. 1 and 2 on an enlarged scale,

Figure 4

2 shows a side view of a second exemplary embodiment in an illustration similar to that in FIG. 1,

Figure 5

3 shows a side view of a jaw insert belonging to FIG. 4 on an enlarged scale,

Figure 6

2 shows a side view of a third exemplary embodiment in an analog representation as in FIG. 1,

Figure 7

a side view of a baking insert belonging to Figure 6 on an enlarged scale, and

Figure 8

a radial section through the object of Figures 3, 5 and 7 along the lines VIII-IIIV.

A press head 1 is shown in FIGS. 1 and 2, which has two base jaws 2 and 3, in each of which a recess 4 and 5, which is delimited by a semi-cylindrical inner surface, is arranged. The entire arrangement is mirror-symmetrical to a plane of symmetry E- in which there is also an interrupted dividing line 6 between the base jaws.

The base jaws 2 and 3 are of identical design and each have a first lever arm 7 or 8, in which the recess 4 or 5 is arranged, and a second lever arm 9 or 10, on the inside of which control surfaces 9a and 10a are arranged which form so-called "inclined planes" with respect to the plane of symmetry E. The two control surfaces 9a and 10a cooperate with a drive device, of which only the two control rollers 11 and 12 are shown here, which are supported on the control surfaces and against one another. By moving the control rollers 11 and 12 from left to right, the press head 1 is brought into the closed position shown. The axial displacement of the control rollers 11 and 12 can be mechanical, electrical, hydraulic or electro-hydraulic happen. The corresponding drive unit is not shown for the sake of simplicity and is otherwise known.

With regard to the interaction of the press head 1 with the pipeline to be processed, it should be noted that the press head is placed on the pipeline to be pressed in that the operator presses the two lever arms 9 and 10 together, which is of course only possible if the control rollers 11 and 12 are in the retracted position. Here, the division joint 6 or the "press jaw" is opened correspondingly wide, and after release a compression spring 13 pivots the two base jaws 2 and 3 as far as the initial diameter of the line connector to be pressed (fittings) allows. In this initial phase of the machining process, the two lever arms 9 and 10 are at a significantly smaller distance from one another than is shown in FIG. 1. By advancing the control rollers 11 and 12, the dividing joint 6 is now brought to close and the pressing process is carried out until the base jaws 2 and 3 assume the position according to FIG. 1.

The lever arms 7/9 and 8/10 are formed with respect to pivot pins 14 and 15, which are held between two T-shaped plates 16. The base jaws 2 and 3 are mounted on these pivot pins 14 and 15 by means of bearings 17 and 18. The press head 1 is fastened to a correspondingly designed drive unit by passing a connecting pin through holes 19 in the two T-shaped plates 16, which engages in a corresponding hole in the drive unit.

In each of the two recesses 4 and 5, a jaw insert 20 or 21 is inserted, the joint of which corresponds to the joint 6 of the base jaws 2 and 3. The inner surfaces 22 and 23 of the jaw inserts 20 and 21 are the so-called work surfaces. In the illustrated embodiment In the external view, the inner surfaces 22 and 23 complement one another to form a polygon with six rounded "corners".

Between the base jaws 2 and 3 on the one hand and the jaw inserts 20 and 21 on the other hand, there are four sliding bodies 24, the sliding surfaces of which run parallel to one another and to the axis A and - as can clearly be seen from the drawing - each with a part of their cross section into the base jaws 2 3 and engage with another part of their cross-section in the jaw inserts 20 or 21. This ensures that the jaw inserts 20 and 21 can be pushed out of the recesses 4 and 5 at a pressure perpendicular to the plane of the drawing according to FIG. 1, wherein they are reliably guided by the sliding body 24.

As can additionally be seen from FIG. 2, the sliding bodies 24 are designed as disc springs 24a and are held in recesses which extend partly into the base jaws 2 and 3 and partly into the jaw inserts 20, 21. The part-cylindrical parts of the disc springs 24a are located in part-cylindrical grooves 25, which have been produced by a disc milling cutter in the base jaws 2 and 3. The sliding surfaces are those surface parts of the sliding body 24 which protrude from the base jaws 2 and 3 and each form two edges which run parallel to the axis A-A. This definition also applies to the differently designed sliding bodies 24 according to FIGS. 4 and 5. The two circular segment surfaces of the disc springs or the center of symmetry in between run parallel to the division joint 6. The base jaws 2 and 3 and the jaw inserts 20 and 21 are drilled through and aligned connected by pins or clamping sleeves 31 with a diameter of 1.5 mm driven into the bores. Each jaw insert 20, 21 is held by two sliding bodies 24 arranged in the vicinity of the dividing joint 6.

In the upper part of Figure 1, a locking element 26 is shown, which consists in a known manner of a locking ball 27 and a compression spring 28, the are mounted in an unspecified, radial to the axis A, bore. The opposing jaw insert 21 is held by a locking element of the same type, which is diametrically opposed to the locking element 26 shown.

Figure 3 shows - on an enlarged scale - a jaw insert 20, the semi-cylindrical outer surface 29 of course match the dimensions of the associated recess 4 or 5, so that the jaw inserts according to Figures 1 and 2 on the one hand and according to Figure 3 on the other hand are interchangeable. In the outer surface 29, two prismatic and axially parallel grooves 25a are arranged, in which the sliding surfaces of the disc springs 24a engage. The inner surface 22 of the jaw insert 20 shown in FIG. 3 is, however, significantly larger in cross section, so that line connectors with a larger cross section can be pressed in with the jaw insert according to FIG.

The exemplary embodiment according to FIGS. 4 and 5 differs from that according to FIGS. 1 to 3 in that, instead of the partially cylindrical disc springs 24a, largely prismatic parallel keys 24b with a rectangular cross section are used, in which the largest planes of symmetry "S" are aligned with the axis AA, at an angle of 30 °. If parallel keys with rounded (semi-cylindrical) ends are used, the axis of curvature is tangential to the outer surface 29, so that the jaw inserts 20 and 21 can be easily threaded.

The position, shape and size of the two parallel axially parallel prismatic grooves 25b for the engagement of the parallel keys 24b for the engagement of the parallel keys 24b are shown in FIG. 5.

In the exemplary embodiment according to FIGS. 6 and 7, the sliding bodies 24 are designed as cylindrical pins 24c and in bores 25c held, which are parallel to the axis AA partly in the base jaws 2 and 3, partly in the jaw inserts 20 and 21. The axis A or AA shown in FIGS. 1 to 8 is the system axis, which, however, corresponds to the axis of the line connector to be processed.

As can further be seen from FIG. 6, the greater part of the bore circumference is located in the base jaws 2 and 3, and in the present case each jaw insert 20 or 21 is held or guided by two sliding bodies 24. The axes of four sliding bodies 24 lie on the corner points of a rectangle R, which is shown here in broken lines. The longest edges K1 and K2 run parallel to the division joint 6. The corresponding diagonals D1 and D2 of the same rectangle intersect in the axes A and A-A, respectively. This basic arrangement also applies to the exemplary embodiment according to FIGS. 4 and 5.

Figure 7 shows - on an enlarged scale - a jaw insert 20, the semi-cylindrical outer surface 29 of course corresponds to the dimensions of the associated recess 4 or 5 in Figure 6, so that the jaw inserts according to Figure 6 on the one hand and according to Figure 7 on the other hand are interchangeable. As a result, the position of the bores 25c also corresponds, some of which are only shown in broken lines in FIG. Only the partial circumference 25d of the bores 25c, which is located within the contour of the jaw insert 20 and likewise forms a groove, is shown in solid lines. The inner surface 22 of the jaw insert 20 shown in FIG. 7 is also significantly larger in cross section here, so that line connectors with a larger cross section can be pressed with the jaw insert according to FIG.

The radial section according to FIG. 8 also represents the jaw inserts according to FIGS. 3 and 5.

FIG. 8 also shows that the inner surfaces 22 of the jaw insert 20 are only arranged on the inner circumference of so-called ribs, while the space between these ribs can be designed quite differently, as can be seen from FIG. However, the geometric shape of the inner surfaces 22 and 23 is predetermined by the nature of the line connector or by the processing guidelines of the manufacturer of these line connections and is not of further importance for the subject matter of the invention. In the cylindrical outer surface 29 of each jaw insert 20 or 21 there is also a recess 30 for the engagement of the detent ball 27 according to FIGS. 1, 4 and 6.

It can be seen that both the semi-cylindrical boundary surfaces of the recesses 4 and 5 and the semi-cylindrical outer surfaces 29 of the base jaws 2 and 3 on the one hand and the jaw inserts 20 and 21 on the other hand can be machined precisely before final assembly, since the sliding bodies 24 are not present at the time of machining are. This allows very precise pairings or fits to be produced, so that the enormous pressing forces can be transferred from the pipeline to the jaw inserts 20 and 21 and from these to the base jaws 2 and 3 without any canting, displacements or the like being observed. It is particularly important here that the inner surfaces 22 and 23 represent a closed curve during the pressing process, ie there are no corners, tips or projections, as would occur if the two jaw inserts were displaced relative to one another. Nevertheless, the two jaw inserts 20 and 21 can be relatively easily pressed out of the recesses 4 and 5 in the direction of the axis AA and replaced by other jaw inserts, which are then fixed again in the exact spatial position by the latching element 26 which engages in the recess 30 . The entire arrangement has, apart from the jaw inserts 20 and 21 to be exchanged, no moving parts or parts which are required during the exchange could get lost. The entire arrangement is very easy to manufacture on modern machining centers.

Because of the easy and precise interchangeability of the jaw inserts 20 and 21, it is sufficient for the user if he has a press head 1 which is suitable for the use of jaw inserts 20 and 21 with the same outside diameters but different inside surfaces. This drastically reduces the weight of tools to be carried by the processor without this having a negative impact on the precision and functionality of the entire pressing device.

The invention is not limited to pivotable base jaws, but can also be used with the same advantage for press heads with base jaws which can be displaced relative to one another by a parallel guide.

Claims (11)

Pressing device for radially pressing line connectors, which have an axis (AA), with two mutually movable pliers-shaped base jaws (2, 3) surrounding a pliers mouth, which are designed as lever arms (7/9; 8/10) and recesses (4, 5), in which on both sides of an uninterrupted dividing joint (6) semi-ring-shaped interchangeable jaw inserts (20, 21), positively secured against rotation, are arranged, the inner surfaces (22, 23) of which are matched to the press profile to be produced on the line connectors, characterized that between the pincer-shaped base jaws (2, 3) on the one hand and the half-ring-shaped jaw inserts (20, 21) on the other hand, at least two sliding bodies (24) are inserted per jaw insert, the sliding surfaces of which run parallel to the axis AA and each with a part of their cross section in the base jaws (2, 3) and with another part of their cross-section into the pincer-shaped jaw Inserts (20, 21) protrude in such a way that the jaw inserts (20, 21) can be pushed out and in along the sliding bodies (24) from the base jaws (2, 3). Pressing device according to claim 1, characterized in that the sliding bodies (24) are selected from the group of disc springs (24a), inserting feather keys (24b), sliding springs and cylindrical pins (24c) and in essentially complementary recesses in the base jaws (2, 3) engage on the one hand and in the jaw inserts (20, 21) on the other. Press device according to claim 2, characterized in that when disc springs (24a) are used, their part-cylindrical part engages in part-cylindrical grooves (25) in the base jaws (2, 3) and their Part bounded by parallel edges engages in complementary grooves (25a) of the jaw inserts (20, 21). Press device according to claim 3, characterized in that the partial circular surfaces of the disc springs (24a) are aligned parallel to the dividing joint (6). Press device according to claim 3, characterized in that the disc springs (24a) are fixed in the base jaws (2, 3) by pins (31). Press device according to claim 2, characterized in that the planes of symmetry of the sliding bodies (24b) are aligned radially to the axis (AA). Press device according to claim 6, characterized in that the planes of symmetry of the sliding bodies (24b) are aligned at an angle of 20 to 45 degrees to the dividing joint (6). Press device according to claim 1, characterized in that when using cylindrical pins (24c) as sliding bodies (24) they are held in bores (25c) which are parallel to the axis (AA) partly in the base jaws (2, 3) and partly in the jaw inserts (20, 21). Press device according to claim 8, characterized in that the larger part of the bore circumference is in the base jaws (2, 3). Press device according to claim 1, characterized in that the sliding surfaces of four sliding bodies (24) lie in the area of corner points of a rectangle (R), the longest edges (K1, K2) of which run parallel to the division joint (6) and its diagonals (D1, D2) intersect in the axis (AA). Press device according to claim 1, characterized in that the jaw inserts (20, 21) are held in the axial direction in the base jaws by locking elements (26).

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