EP1095739A2 - Press tool and method of cold-working a connection between workpieces - Google Patents

Abstract

The press tool for bonding two pipe workpieces (2,3), in a cold shaping action, gives bonding zones at the circular outer circle shapes of the pipes (2,3) which are pushed into each other.. The press pads (10) match the outer cross section shape of the workpieces, when closed together, and can have openings (13,17). The press tool can also have two press pads (10) and a mounting bolt. On applying the press force (F), the cold shaping forces are transferred to the workpieces (2,3). The gap (A) between the press pads (10) is adjusted according to the mfg. tolerances of the workpieces (2,3).

Description

The invention relates to a pressing tool according to the preamble of the claims 1 and 4 and a method for cold forming joining after Preamble of claim 11.

Such pressing tools are also available as press chains, press slings or Press rings are known and are used in particular for connecting pieces of pipe used. For this purpose, the pipe ends to be connected are in one deformable sleeve, a so-called press fitting, pushed. To the cold-forming connections, the press jaws are initially placed like one Cuff that remains open at one point around the press fitting, taking in the open place the two chain ends of the pressing tool face to face opposite. The introduction of the driving forces causes Pulling the two chain ends together. This will make the inside of the Press jaws brought together to an annular pressing space and transfer the cold forming forces to the press fitting. To one if possible to ensure uniform radial cold forming of the fittings in practice today for the cold forming joining of pipes with one Diameters greater than 54 mm at least three, usually chain-like arranged press jaws used.

EP 627273 describes a pressing tool with more than two pressing jaws, which are partially movable in the circumferential direction in a link guide, whereby the press jaws are evenly arranged over the circumference and thus enable a uniform radial distribution of the forming forces and prevent burr formation between the pressing members.

Auslaufen" des Pressfittings bzw. eine Bildung eines Pressgrates zwischen den Stirnseiten der Pressbacken beim Schliessen des Presswerkzeuges verhindert werden, was ein vollständiges Schliessen und damit verbunden ein zuverlässiges Verbindungen verunmöglicht hat. As shown in EP 627273, press tools for cold-formed pipe connections with larger outside cross-sectional diameters, in particular for line systems with high internal pressure loads, require more than two press jaws. So could one

Leakage "of the press fitting or the formation of a press burr between the end faces of the press jaws when the press tool is closed can be prevented, which has made it impossible to completely close and, in connection with this, reliable connections.

Such pressing tools are for example in DE 4240427 and EP 922537, also in so-called self-retaining designs, which itself before the introduction of the driving forces by spring elements pull the pre-tensioning forces together and therefore not alternatively to Example with one hand, must be held on the workpiece in order to To prevent slipping or falling off the connection point.

The invention has for its object to provide an easy to use to create a structurally simple and flexible press tool or a method for cold-forming joining of nested Describe workpieces, which is a safe and reliable connection of workpieces with larger external cross-sectional shapes as well Connections with relatively extensive cold forming possible. Such Crimping tools should also be usable in confined spaces and, if necessary, grasp the workpieces to be joined in a friction-resistant manner.

According to the invention, this object is achieved by the characterizing features of claims 1, 4 and 11 solved. Beneficial and alternative Embodiments of the invention are in the dependent claims cited.

The pressing tool according to the invention has at least two arms, the pressing jaws also being advantageous for forwarding the introduced ones Driving forces are used. The press jaws must face each other be movably connected, the connecting ends of the Press jaws over bearing bolts as structurally simple and reliable Connection concept has proven.

The cold forming forces exerted by the press jaws on the workpieces are triggered by drive forces introduced into the tool. For the Introduction are areas of attack - such as recesses, holes, projections, Eyelets, hooks, etc. - at at least one point on the press tool to provide. These can be on the non-bearing ends of press jaws for attaching an optionally connectable drive device to be appropriate.

If, for example, possibly with tubular workpieces predetermined, in particular circular, outer cross-sectional shapes mentioned are always workpieces with such a trained Understand connection areas.

A pressing tool according to the invention exerts the cold forming forces on the workpieces via the inner sides of the pressing jaws in such a way that when the pressing jaws move against one another Leakage "of the outer workpiece and thus the formation of a press burr between the press jaws is largely prevented. So that the front inside edges of the press jaws do not cut into the workpiece and thereby trigger press burr formation, they are at least on one side, if necessary also on both sides, for example in the end faces Bordering areas of the inner sides are provided with recesses which are angled outwards, for example widening towards the end faces, and the inner sides can be both angled outward towards the front inner side edges and also convex, if necessary gradually curved towards the inner side edges, rotating outwards The internally breaking away, possibly angled, outward sides can be designed as insertion bevels adjoining the front inner side edges, which are angled insertion bevels depending on the processing preferably flat, but can also be slightly concavely curved. If the insertion bevels are slightly concave, their curvature is less pronounced than that of the rest of the inside, for. B. a lateral surface segment of a rotating body, possibly also less than the outer cross-sectional diameter of the outer workpiece before cold forming, while the curvature of the inner side regions adjoining the insertion bevels corresponds at least approximately to the remaining outer cross-sectional diameter of the cold-formed workpiece.

Due to these features, the insertion bevels on the inside are on your front inside edges so shaped that when applied to the Do not work the inside with the front inside edges sit on, but inside, possibly tangentially, optionally spaced from the front inside edges, on Fit the outer jacket of the workpiece.

The extent of the outward angling of the outer end face Inner side areas depend on the outer cross-sectional diameter of the respective workpieces assigned to the pressing tool. At External cross-sectional diameters between 54 mm and 108 mm can Entry bevels, for example at an angle of 5 to 25 ° to the outside be angled to the directly adjacent surface.

At least two are required for the function of a pressing tool according to the invention Press jaws necessary. The two press jaws can by one common bearing pin can be mounted, the bearing pin if necessary is eccentric. An eccentrically designed bearing pin causes that when the pressing tool is opened, the non-bearing end faces of the Press jaws experience an additional translational movement apart. As a result, the necessary opening angle for an extent of the Workpieces and the distance between the end faces in the preloaded state of the Tool can be reduced.

The two press jaws can also have two in one bearing bracket held bearing bolts are stored individually. Here again if necessary, at least one bearing pin can be formed eccentrically. The both bearing bolts are both rigid in the bearing bracket, as well can be stored coupled together. For example, to move relative A guide slot is provided in the bearing bracket for each bearing pin be along which the bearing pins are displaceable, and if necessary the Bearing pin to be connected via a guide linkage.

The eccentric design of the bearing bolts and the individual bearings of the Press jaws are also suitable for those embodiments in which the The inside of the press jaws does not have surface segments of Have bodies of revolution, i.e. that the press tool in the closed Instead of an annular space, it has a polygonal or oval shape encloses the trained room.

To create the pressing tool around the workpieces to be connected facilitate and in particular its falling before starting a if necessary to prevent coupling device, it is advantageous, the pressing tool in the closing direction with pretensioning forces to provide exercising agents. For the self-holding function of a Press tool is at least one pretensioning force in the closing direction exercising agent necessary. This can be between the individual Press jaws can be arranged and / or the pressing tool as one-sided Clamp open clamp. Since the means exerting the preload on the one hand, the pressing tool on the workpieces does not slip has to clamp, and on the other hand the press tool is still slightly closed opening and to place the workpieces, preloads are exerted Medium with relatively long spring travel is an advantage. This is preferred Coil springs versus leaf or bar springs, especially at Pressing tools where the opening of the tool is large Relative movements require fewer parts. As a preload Different components made of different, elastically deformable materials. Metallic springs are preferred, however also means made of rubber-like materials such as drawstrings or stretchable Plastics are conceivable. You can between the press jaws and / or around these are attached outside. Wound around bearing bolts Coil springs, the spring ends of which each on a press jaw Applying pre-tensioning forces allows for structurally simple solutions comfortable handling.

The shape of the inside of the pressing jaws of the pressing tools is not on Shell surface segments of rotating bodies with identical Radii of curvature limited. Are the workpieces in the connection area not rotationally symmetrical, but for example ellipsoid, polygonal or irregularly shaped, or should it be shaped into such a shape are other, the external cross-sectional shape of the workpieces suitably adapted training of the inside is possible.

To support the positioning and guiding of the pressing tool Workpieces can also on the inside of the press jaws - if necessary, the entire inside circumferential protuberances and / or Recesses such as Notches or grooves may be arranged.

Because the press jaws can be designed in a very narrow design and around their Bearing bolts are largely pivotable freely, that is the inventive Not only to place the pressing tool simply and easily around workpieces, but also for confined spaces, such as those found in wall and installations on the ceiling and in corners can be found, particularly suitable.

An inventive, cold forming joining process from two to part nested workpieces with a predetermined, in particular circular outer cross-sectional shape, takes into account the given Manufacturing tolerances of the workpieces to be connected in the connection area. Due to the tolerances of fittings, sleeves and pipes, for example, especially with the large connection nominal sizes DN (50 to 100) the necessary driving forces for merging the Press jaws of a press tool to a closed press room vary considerably. This makes the drive devices and tools to be dimensioned according to the maximum occurring forces. in the In contrast, the inside of the press jaws are one Press tool according to the invention designed so that a reliable, cold forming connection when a predetermined force is reached, even at a tool that is not closed. in the Interaction with a drive device, which for the respective Connection processes specific driving forces on the tool can be initiated are controlled connections with lighter and more flexible Tools and drive devices possible.

Fig. 1

einen Querschnitt durch ein erfindungsgemässes Presswerkzeug, welches zwei zu verbindende Werkstücke umfängt;

Fig. 2

einen vergrösserten Ausschnitt einer Pressbacke des Presswerkzeuges aus Fig. 1;

Fig. 3

einen Querschnitt durch das Presswerkzeug und die Werkstücke aus Fig. 1, auf welches Antriebskräfte eingeleitet sind;

Fig. 4

einen Radialschnitt durch eine Ausgestaltungsform der Innenseite einer Pressbacke;

Fig. 5

einen Querschnitt durch ein Ausführungsbeispiel eines erfindungsgemässen Presswerkzeuges mit zwei Lagerbolzen und

Fig. 6

einen Querschnitt durch ein Ausführungsbeispiel eines erfindungsgemässen Presswerkzeuges mit drei Pressbacken.

The invention is described below purely by way of example with reference to exemplary embodiments shown in the drawing.
Show it:

Fig. 1

a cross section through a pressing tool according to the invention, which includes two workpieces to be connected;

Fig. 2

an enlarged section of a press jaw of the press tool of FIG. 1;

Fig. 3

a cross section through the pressing tool and the workpieces of Figure 1, to which driving forces are introduced.

Fig. 4

a radial section through an embodiment of the inside of a press jaw;

Fig. 5

a cross section through an embodiment of a pressing tool according to the invention with two bearing bolts and

Fig. 6

a cross section through an embodiment of a press tool according to the invention with three press jaws.

Fig. 1 shows a tubular fitting 2, which in part on a pipe 3 circular outer cross-section is pushed on. Because of your Manufacturing tolerances are between the fitting 2 and the pipe 3 each different sized empty space 9 available. The fitting 2 can be a Be gunmetal or machined from a corresponding blank be made. A pressing tool according to the invention has two Press jaws 10, a coil spring 5 and a bearing pin 4. The Pressing tool surrounds the fitting 2 and lies on the coil spring 5 biased to the fitting 2 in the biased condition. The press jaws 10 are essentially identical in mirror symmetry. You point same features with the same functions and reference numbers. The Press jaw 10 is semicircularly curved. On a warehouse side Front 16 of the press jaw 10 are bearing tabs 14, if necessary attached in pairs and symmetrically to the median plane, which with a Bore are provided. A non-bearing end face 11 forms this other end of the arcuate press jaw 10. The press jaw 10 has in Area of the non-bearing end face 11 directed against it Attack area 18 for introducing drive forces F (as in FIG. 3 shown). For the introduction of preload forces through a spring end the screw end 5 in the press jaw 10 is on the end face 16 adjacent introductory area 15 is provided. For better management of the The introduction region 15 can be provided with a groove at the spring end. Two parallel side walls 19 which act as stiffening ribs give the press jaw 10 additional rigidity. The press jaw 10 has an inner side 12, the surface of which by a lateral surface half Rotational body and by two bevels 13, 17 is determined. It are also training with only one bevel or according to the Fig. 5 without any bevels, especially for connections of medium and smaller outer cross-sectional shapes possible. In a manner known per se the bearing tabs 14 on the bearing end faces 16 of the two Press jaws 10 each offset from one another, so that the Bores of all bearing plates 14 are aligned coaxially with each other can. The bearing pin 4 inserted in the aligned bearing holes connects the two press jaws 10 rotatably supported with each other. So that will the fitting 2 can be encompassed by the pressing tool. In the coil spring 5 several turns around the bearing pin 4 conducts prestressing forces into the Introductory areas 15 of the two press jaws 10. As a result, the two lie Press jaws 10 on the fitting 2 frictionally and secure the pressing tool against slipping or falling.

FIG. 2 is an enlarged section of FIG. 1 and shows one possible one Design of the inside 12 with inventive bevels. The Inside 12 is in the form of a lateral half of a cylinder from Diameter D formed. From this shell surface half is from the to non-bearing-side end 11 bordering area of the inside 12 a bevel 13 not on the bearing side. The non-warehouse side Bevel 13 widens towards this end face 11. The non-bearing-side bevel 13 is on a length L from the The outer surface shape of the inside 12 is excluded and with an angle W formed inclined against this lateral surface. The not shown in Fig. 2, on the bearing end face 16 area can be a Mirror-symmetrically identical bevel 17 on the bearing side exhibit. The edges of the bevels 13, 17 with the end faces 11, 16 can be provided with a radius. This will slip the Press tool 1 on the fitting 2 facilitated. Is in the prestressed state the tool on the bevels 13, 17 on the fitting 2.

Below are dimensions of the diameter D, the angle W and the length L for an embodiment of press jaws 10 according to the invention for the nominal widths DN (German standard) 40, 50, 65, 80, 100, 2 1/2 ", 3", 4 "of System provider Viega, Franz Viegener II, D-57428 Attendorn "and also for the nominal sizes DN 40, 50, 65, 80, 100 of the system provider mapress, Mannesmann Pressfitting-System, D-40764 Langenfeld "compiled in tabular form, which have proven suitable for cold-forming connections with a press tool, corresponding to the embodiment in FIG. 1. D, W, L depending on nominal size DN, pipe and fitting Nominal size [DN] Pipe [material] Fitting [material] Diameter D [mm] Angle W [360 °] Length L [mm] 40 Edelst./Cu Edelst., Rotg. / Cu 51.9 7.5 2-3 50 Edelst./Cu Edelst., Rotg. / Cu 63.9 8.5 3-4 65 Edelst./Cu Edelst., Rotg. / Cu 76.1 12.5 4-8 80 Edelst./Cu Edelst., Rotg. / Cu 102.0 12.5 4-8 100 Edelst./Cu Edelst., Rotg. / Cu 121.0 15.0 4-8 2½ " Edelst./Cu Edelst., Rotg. / Cu 78.0 12.5 4-8 3 " Edelst./Cu Edelst., Rotg. / Cu 91.5 12.5 4-8 4 " Edelst./Cu Edelst., Rotg. / Cu 116.5 15.0 4-8

FIG. 3 shows the pipe 3, the fitting 2 and the pressing tool from FIG. 1 in the driven state. Driving forces F are not greater than one in FIG shown, for example, detachable drive device on the Attack areas 18 of the pressing jaws 10 are introduced into the pressing tool. Starting from the prestressed state of FIG. 1, the Press jaws 10 against each other. The bevels 13, 17 lie on the Surface of the fitting 2 and exert forming forces on the fitting 2. Between the edges between the end faces 11, 16 and Bevels 13, 17 and the surface of the fitting 2 is a certain Given scope. This will prevent the formation of a ridge between the opposite end faces 11, 16 substantially prevented. Through the Forming forces exerted by the pressing tool is the fitting 2 in essentially oval-shaped until it reaches the lateral surface halves of the Inside 12 touched. By moving the Press jaws 10, the fitting 2 is further formed until it is completely on the Shell surface halves abuts. Since their diameter D (Fig. 2) is smaller than the outside diameter of the fitting 2 flows with these deformations Material of the fitting 2 against the pipe 3. With another Moving the pressing jaws 10 against each other flows next to the material that is in the bevels 13, 17 flows, further material inwards and exercises Compressive forces radially on the tube 3. The tube 3 is now with the cold-formed fitting 2 reliably connected. Another Moving the pressing jaws 10 against one another now increases the driving forces F disproportionately high, even if the pressing jaws 10 with their Do not touch non-bearing end faces 11 and a distance A from each other. Given driving forces F, the distance is A of the manufacturing tolerances of the dimensions in the connection area of the Fittings 2 and the tube 3 dependent.

The cold-forming process according to the invention is based on this fact Connection method for partly pushed work pieces. in the Contrary to the pressing tools common today, for one reliable connection of the workpieces does not last as long initiated until the press jaws have touched each other, but the Press jaws 10 are moved against each other until the driving forces F have reached a predetermined amount. A corresponding The drive device therefore has an adjustable regulation of the maximum to be initiated drive forces F and not, for example, only one, as in the Common practice, designed for a certain maximum pressure mechanical pressure relief valve, which is only a constant upper limit for the Guaranteed amount of driving forces. As is easy to see, the Diameter D (Fig. 2) with the extreme values of the manufacturing tolerances Dimensions of the workpieces that the cold forming joining influence, so that it is always a reliable, cold forming joining is guaranteed, both when the non-bearing end faces 11 - depending on the tolerance conditions - except approach a distance A, as well as when the end faces 11 touch. As Example is for a connection of, for example, a gunmetal fitting with a stainless steel tube - with a nominal diameter of 108 mm - with a tool which is essentially that shown in FIG Embodiment corresponds, the distance A is usually about 2 mm +/- 1 mm. The driving forces required for cold forming are in one On the order of approximately 32 kN.

Fig. 4 shows a radial section along the line I-I of Fig. 3 with viewing direction in the direction of the arrow through a possible design variant of a press jaw 10. Depending on the design, the inside 12 can have a circumferential, have semi-toroidal protuberance 22 or a circumferential notch 23. The inside 12 is covered by a surface segment of a rotating body certainly. The protuberance 22 and the notch 23 are in the range of Bevels 13 continued parallel to these. The semi-toroidal Protuberance 22 supports the positioning and guiding of the press jaw 10 on a corresponding fitting 2 during cold forming joining. The Notch 23 is provided for a possible bulge of the fitting 2.

5 shows a further exemplary embodiment of an inventive one Press tool, the two mirror-symmetrically designed, single-bearing Press jaws 20, in contrast to the press tool from FIG. 1, over two Bearing pins 4 are each individually rotatably mounted. The two bearing bolts 4 are in turn mirror-symmetric in a manner known per se identically designed bearing brackets 7 held. The both sides of the individually mounted press jaws 20 are mounted mounting brackets 7 each with two bearing bores. In the plane of symmetry between the two bearing bolts 4 have bearing holders 7 on the inside guides for a role 8 on. The roller 8 engages in a semi-cylindrical shape Recess 28 of the bearing end 26 of both individually supported Press jaws 20 and thus force this to open symmetrically Pressing tool. If necessary, training variants are included Bevels (Fig. 2), especially for large tools Connection diameter to be considered. Two mirror-symmetrical identically designed coil springs 5 which lead around the bearing bolts 4 20 prestressing forces in the individually stored press jaws, which the Position the press tool on a fitting in a self-retaining manner.

6 shows a further exemplary embodiment of an inventive one Press tool, which in contrast to the press tool of FIG. 5 three has pressing jaws connected to one another in a chain-like manner. Two Arc-shaped end jaws 30 are of identical design and are of mirror symmetry one end with the ends of a third arcuate central jaw 31 two bearing pins 4 rotatably connected to each other in a conventional manner. In the non-bearing-side end area of the end jaws 30 are analogous to that Press jaws 10 from Fig. 1, areas of attack 38 for the initiation of Driving forces F attached. The end jaws 30 and the middle jaw 31 can have essentially identical inner sides 12 with lateral surface segments of rotary cylinders, provided with bevels 13, 17. Two mirror-symmetrically identically designed, the bearing bolts 4 wrapping around Coil springs 5 lead into the end jaws 30 and into the middle jaw 31 in Closing direction preload forces, which press tool on a fitting position self-holding.

Claims (11)

Press tool for cold forming joining of, if necessary tubular, at least partially pushed into one another (2, 3) with a predetermined, in particular circular, External cross-sectional shape, which pressing tool on at least two these workpieces press jaws (10, 30, 31), the inner sides (12) of which in the closed state Press tool essentially the outer cross-sectional shape have, characterized in that at least one of the Inside (12) at least one widening recess (13, 17) for Part of what flows during cold forming Workpiece material and / or as a chamfer for burr-free Has the workpieces (2, 3) encompassed by the pressing tool. Press tool according to claim 1, characterized in that the in each case on the end faces (11, 16) of the press jaws (10, 30, 31) bordering areas of the inside (12) attached, expanding Recesses (13, 17) as angled outwards against the End faces (11, 16) are designed to widen bevels. Press tool according to claim 1 and 2, characterized in that the inner sides (12) of the press jaws (10, 30, 31) - optionally with Except for the widening recesses (13, 17) - Have lateral surface segments of rotating bodies. Press tool for cold forming joining of, if necessary tubular, at least partially pushed into one another (2, 3) with a predetermined, in particular circular, External cross-sectional shape, which pressing tool on at least two these workpieces press dies (10, 20) has, characterized in that two and only two in essentially semi-circular press jaws (10, 20) are hinged together at one end and at the other end, if necessary, coupling areas, for the the cold forming has the necessary driving forces (F). Press tool according to one of the preceding claims, characterized characterized in that the press jaws (10, 20, 30, 31) over at least a bearing pin (4) are connected. Press tool according to claim 5, characterized in that this Bearing pin is eccentric. Press tool according to one of the preceding claims, characterized characterized in that the pressing tool is placed on the pressing jaws (10, 20, 30, 31) exerting prestressing forces, if necessary between the Press jaws attached, means is biased in the closing direction. Press tool according to claim 7, characterized in that the Means which exert the prestressing forces, springs, are preferred Coil springs (5). Press tool according to claim 8, characterized in that at least one coil spring (5) wrapping around a bearing pin (4), is appropriate. Press tool according to one of the preceding claims, characterized characterized that in the applied state, after the cold forming connecting the workpieces (2, 3) by the initiated driving forces (F), the end faces (11) of at least two Press jaws (10, 20, 30) are spaced apart. Method for the cold-forming connection of optionally tubular, at least partially pushed workpieces (2, 3) with a predetermined, in particular circular, external cross-sectional shape using a pressing tool according to one of the preceding claims, with the following steps: Opening the pressing tool, if necessary against the prestressing forces acting in the closing direction; Encircling the workpieces (2, 3) by the pressing tool; and introducing the drive forces (F) into the intended engagement areas (18, 38) of the pressing jaws (10, 20, 30) for cold-forming connection of the workpieces (2, 3) by means of a drive device, which can be coupled, if necessary, characterized in that the cold forming as soon as a certain driving force (F) dependent on the respective materials, manufacturing process and dimensions of the workpieces (2, 3) is reached - even if the pressing tool is not yet closed - or, should this certain driving force (F) still have not been reached, is ended when the pressing tool reaches the closed position.

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