Press tool.

The invention relates to a press tool, in particular for connecting tubular workpieces, with more than two arcuate press jaws that are so movable relative to each other that they can be opened for placing on the workpiece and that they complement each other towards a closed pressing chamber for pressing end, and with at least one drive means for moving the cheek plates in the pressing direction.

For connecting pipe ends coupling sleeves are used, which are plastically deformable and are made of metal, preferably of steel. Their internal diameter is so much greater than the outer diameter of the pipe ends to be that they are deformed in the radial compressibility to the concerns on the lateral surface of the pipe ends consistently. According to DE-PS 1 187 870, such coupling sleeves can on its inside in the vicinity of each end additionally have an annular groove into which an elastic sealing ring is inserted.

The radial compression is done by P reßwerkzeugen, as are known for example from DE-PS 21 36 782nd This pressing tool has two two-armed each formed clamping jaws, of which at least one is mounted pivotably on the pressing tool. The cheek plates have circular arc portions forming pressure surfaces on with equal radii, which include a press room. Instead of a circular arc sections, the press surfaces can be contoured to form, for example a polygonal or oval baling chamber.

The press room the distant arms of the press jaws can be spread against the action of a spring, with the result that the pressing jaws are moved in the range of the baling chamber to today. The spreading is done by means of juxtaposed and abutting pressure rollers, which are driven together by a drive device in the form of a working cylinder between the arms and pivot in this way the pressing jaws.

Further development of this press tool is described in DE-OS 34 23 283rd In this press tool two press jaws are provided which are pivotably mounted in each case on a drive lever, which in turn are pivotably guided on the pressing tool. The drive lever have opposing arms which can be spread apart by means of a working cylinder can be moved into the space between pressure rollers and in this way to move the cheek plates together. The press jaws are additionally performed in scenes so as to be pivoted during the pivoting of the drive lever in the opening direction to their points of articulation to the drive levers, so that a broad, mouth-like opening is formed between the end faces of the cheek plates, which respectively receive the pipe ends to be a coupling sleeve easier.

During pivoting of the drive lever in the reverse direction, the jaws are again pivoted so that the center perpendicular one another fall on their arc sections about and the jaws are moved in parallel during the further pivoting of the drive lever to today. During the pressing jaws are further moved toward each other until they include a circular area on the pressing end while the pipe ends and the coupling sleeve are deformed in accordance with reduction in diameter.

This pressing tool has proven desirable if a not too large diameter reduction or pressing depth is required. For larger offsets that are required when the pipe joint is to withstand higher internal pressures, it is recommended to provide more than two pressing jaws, so that it does not come between the end faces of the cheek plates to form outwardly projecting webs which a complete closing of the press jaws would prevent. Such dies are described for example in DE-OS 21 18 782, DE-OS 35 13 129, DE-AS 25 11 942 and DE-AS 19 07 956th Allen disclosed therein pressing tools have in common is that all pressing jaws are movable and guided in the radial direction. This requires elaborate guides and drive means whereby the dies are heavy and therefore difficult to handle and also expensive.

The invention is accordingly based on the object to make a press tool of the aforementioned type so that it is in spite of the arrangement of more than two press jaws designed as simple and thus easy to handle and inexpensive to produce.

This object is achieved in that one of the pressing jaws is designed as an attachable to the workpiece abutment and that the other cheek plates by means of or the drive device (s) can be moved and guided in such a way that they do to the pressing continuously towards moving the center of the pressing chamber in the closed state of the pressing tool, wherein the abutment is formed as befindlicher at the free end of the die abutment bracket which is mounted pivotably on one side and detachably on the opposite side or lockable. This abutment bar can be pivoted away when the mold is attached to the tube ends to be joined or to the coupling sleeve. After swinging back and locking then the movable pressing jaws can be moved by the drive means in the direction of the abutment. It is advantageous when the press jaws are movably guided each other that their respective adjacent opposite faces to the onset of pressing have the same distances.

The mold according to the invention is characterized by simple structure, since one of the cheek plates is formed as an abutment and thus requires neither a guide nor a drive device. The rest of the press jaws are guided and driven so that they move in the pressing process in certain directions, on the center of the pressing chamber in the closed state of the press tool out. This is essential to it that act the same forces on the workpiece from all sides.

In embodiment of the invention provides that the cheek plates in the circumferential direction have the same length arc segments, the gaps between the respective opposite end faces of the cheek plates are equally distributed over the circumference.

If three press jaws are provided, the directions of movement of the movable pressing jaws should form an angle of 60 °, which is symmetrical to the center line perpendicular to the abutment and opens from this face away. In four press jaws, the movement directions of both the abutment adjacent press jaws should include when pressing an angle of 90 °, which is symmetrical to the center line perpendicular to the abutment and opens from this face away.

In a further embodiment, it is provided that the movable pressing jaws abut one hand at predetermining by their directions of movement guide means and on the other hand to a movable towards the abutment ram, which is connected to the or to the drive device (s) and on which the abutment adjacent pressing jaws are slidably mounted. The possibility exists, that between the press ram is displaceable for pressing jaws a further cheek plate rests on the press ram or is connected to this, which faces the abutment. The ram is part of the drive device and can for example be designed as a hydraulic cylinder or connected to such. Instead of such a press ram can for each movable pressing jaw a separate drive means may be provided, for example, again in each case a hydraulic cylinder. This may include a pressing or Zugstempel.

In the drawing the invention using an exemplary embodiment is illustrated in more detail. Show it:<dl id="dl0001"><dt>figure 1</dt><dd>a press tool in the open position and</dd><dt>figure 2</dt><dd>the mold according to Figure (1) in the closed position.</dd></dl>

In Figures 1 and 2, a press tool 1 is shown, namely the upper head portion. It comprises a tool housing 2, which is formed hollow and initially widens in the downward direction and then is tapered. In the central region, it has a U-shaped recess. 3

The free ends of the recess 3 are connected by an abutment bracket. 4 The abutment bar 4 is pivotally mounted on its right side in this view to a bearing bolt. 5 On the left in this view side of the abutment bracket 4 is fixed by a locking pin 6 in the position shown. This locking pin 6 passes through corresponding recesses in the tool housing 2 and the abutment 4 and can be easily removed. After his removal of the abutment bracket 4 can be pivoted about the bearing pin 5 in the directions of the double arrow A, namely clockwise so far that the recess 3 is completely open at the top.

On the inside of the abutment bracket 4 has a pressing surface 7, the circular arc shape and extends over an angle of 120 ° symmetrical to the longitudinal axis of the die. 1 The pressing surface 7 has a circumferentially extending, inwardly open groove. You may be replaceable attached to the abutment bracket. 4

Inside the tool housing 2 extending oblique guide surfaces 8, 9, enclose an angle of 60 ° and extend mirror-symmetrically to the longitudinal axis of the die. 1 lie on the guide surfaces 8, 9 each have a press jaw 10, 11 to, through correspondingly inclined abutment surfaces 12, 13. The cheek plates 10, 11 are also formed mirror-symmetrically to the longitudinal axis of the die 1 and each have a pressing surface 14, 15 which each as over 120 ° extending arc sections are formed. On the inside, a circumferential groove is formed also in it. The circular arc portions of all press surfaces 7, 14, 15 have identical radii. The cheek plates 10, 11 extend down side into a horizontal and transverse to the longitudinal axis of the die 1 extending guide groove 16 which is formed in the head 17 of a pressing die 18th The lower surfaces of the cheek plates 10, 11 also run horizontally, so that the cheek plates 10, 11 are transversely displaceably guided in the groove 16 to the longitudinal axis of the die 1 in the groove 16, and specifically in the manner of a dovetail guide locking manner.

In the lower portions of the cheek plates 10, 11 are transverse blind holes 19, 20 formed, coaxially to each other. In these blind holes 19, 20 a compression spring 21 is used, which tends to the cheek plates 10, 11 outwardly and thus the abutment surfaces 12, 13 to press against the guide surfaces 8, 9th The ram 18 is 1 (double arrow B) mounted vertically linearly movable along the longitudinal axis of the die. It is operated by a pneumatically or hydraulically operated working cylinder, which is not shown here.

first the locking of the abutment bracket 4 is achieved by means of the locking bolt 6 for the use of the die 1, that this locking pin 6 is pulled out and the abutment bar 4 pivoted so far clockwise until the fork-shaped opening of the recess 3 is completely free. At the same time the punch is 18 in a retracted downwards Sellung. The mold 1 can then be attached to a coupling sleeve 22 so that the clutch sleeve 22 extends perpendicularly to the drawing plane by the recess 3 and taken up by this. Then, the abutment 4 is pivoted about the coupling sleeve 22 and locked by inserting the locking pin 6th The coupling sleeve 22 is then enclosed by the press tool. 1

The cheek plates 10, 11 are then brought by ramping of the ram 18 on the coupling sleeve 23 to the plant. Since its radius to the intended depth of pressing is smaller than the radius of the coupling sleeve 22 prior to pressing, the press surfaces are 7, 14, 15 only with their outer transverse edges at the periphery of the coupling sleeve 22nd are still free gaps 23, 24, 25 that are the same size between the faces of the cheek plates 10, 11 and the abutment bracket. 4 The radii of the circular arc portions of the pressing surfaces 7, 14, 15 go out of center points which lie in the vertices of an equilateral triangle.

Through further pressurizing the ram will now be 18 moved up. The cheek plates 10, 11 to slide it over their contact surfaces 12, 13 on the guide faces 8, 9, whereby them extending in the directions of the double arrows C, D movement direction is impressed. The two directions of motion include the same angle as the guide surfaces 8, 9, ie 60 °. In this case, 11 to slide the press jaws 10, in the groove 16 of the punch 18 at the same time horizontally toward each other, against the action of compression spring 21. In this manner the coupling sleeve 22 is radially compressed, that is reduced in its diameter to the desired depth of pressing. On pressing end a circular baling chamber is of the press surfaces 7, 14, 15 and included the gaps 23, 24, 25 have been reduced to zero.

For the removal of the press tool 1 of the coupling sleeve 22 of the ram 18 is moved back. The abutment bar 4 is pivoted away, after removal of the locking pin 6 so that then the pressing tool 1 can be taken away.