Press tool.

The invention relates to a press tool for connecting tubular workpieces with more than two pressing jaws, the thus being relatively movable with the aid of at least one driving means that, from an open position in which the pressing device on the workpiece can be placed, in a pressing position can be brought in the cheek plates combine to form a closed pressing space.

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 11 87 870, 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 pressing tools, such 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.

A further development of this press tool is the pressing tool is according to the preamble of claim 1 and 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 by means of a working cylinder can be moved into the gap pressure rollers and move the pressing jaws towards each other in this way. 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 Antriebshebei 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 necessary 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 the pressing jaws are connected articulated together to form a press ring, the pressure ring between two pressing jaws open and the means and the drive device (s) can be closed under contraction of the press ring.

This embodiment opens up the possibility that the drive device (s) is formed by the pressure ring or are separated, and the drive device (s) and the pressing ring comprise coupling elements via which they are connected can be brought into operative connection. The mold is then constructed in two parts, wherein the wraparound ring initially placed around the workpiece and then the driving means is attached to the press ring. The mold is very advantageous in its handling because the items have a much lower weight and are independently handled.

Here, the pressing ring may have at least one outer side of at least the movable pressing jaws fitting tieback, or about which the pressing jaws zusammenbewegbar, for which purpose two drawstrings may be provided. This embodiment is particularly weight- and cost-saving.

Thus, the front-side distances of the press jaws are exactly the same at the beginning of the pressing operation is proposed according to a further feature of the invention that at least a part of the pressing jaws is guided in Preßbackenträgern relative to this movable with corresponding guide means may be provided which guarantee that the frontal distances of the press jaws at the beginning of the pressing operation are the same. The press jaws can be guided to move in the circumferential direction substantially. As guide means come sliding guides, but also an anti-stops spring action in question.

Finally, it is provided according to the invention that the compression jaws are formed of equal length in the circumferential direction, so that the gaps between the respective opposite end faces of the pressing jaws are uniformly distributed over the circumference.

In the drawing, the invention is further illustrated with reference to embodiments. Show it:<dl id="dl0001"><dt>figure 1</dt><dd>each half illustration of two pressing tools in the open position;</dd><dt>figure 2</dt><dd>the dies according to Figure 1 in the closed position.</dd></dl>

In Figures 1 and 2, two dies 91, 92 are shown, respectively in half. On the left half of the symmetry axis of the figures 1 and 2, the pressing tool shown 91 and on the respective right half of the pressing tool 92nd Both dies 91, 92 are mirror symmetry, so that its construction follows from the representation of their halves.

The mold 91 illustrated in the left half of the figures 1 and 2 comprises a pressure ring 93, consisting of a total of three press jaws 94, 95, with 94 only partially and a press jaw because of the half-page display the cheek plate - namely the right - not to are seen. On the top press jaw 94 an existing made of spring steel, flexible tension band 97 is attached by a screw 96, which extends over the periphery of the top press jaw 94 and the left pressing jaw 95th A corresponding tension band extends to the other, not shown side of the press ring 93rd

The lower cheek plates 95 are guided in the circumferential direction K displacement on the drawstrings 97th In each case a rubber spring 98 summarizes in recesses in the opposing end faces of the cheek plates 94, 95 and is vulcanized to the latter. In unloaded condition, the press jaws 94, 95 are pushed apart by the rubber springs 98 by a certain amount, so that may arise between the opposite end faces of the cheek plates 94, 95 column 99, 100 of the same width when the cheek plates 94, 95 outside on a coupling sleeve 101 rest.

At the free ends of the drawstrings 97 coupling tabs 102 are attached on the outside. These coupling approaches 102 drive means only schematically here and shown in broken lines 103 can be recognized, which is separated from the pressing ring 93rd The mold 91 thus consists of two independent parts that can be coupled together.

The drive means 103 includes two drive lever 104, of which only the left one is visible. They are rotatably mounted about perpendicular to the plane extending pivot pin 105. Their downward arms 106 are spread to pivot in the direction of arrow L, and against the action of a not illustrated here, the lower arms 106 puckering spring. For spreading the arms 106, a pair of pressure rollers is used, which in the space between the arms can be retracted by means of a pneumatically or hydraulically pressurizable working cylinder 106. Such a drive device is known per se from DE-PS 21 36 782 and DE-OS 34 23 382nd The from the pivot pin 105 upwardly extending arms 107 are shaped so that it approaches the coupling 102 can engage behind.

In use of the die 91 of the press ring 93 is first opened, so that the lower cheek plates 95 protrude outward, as is shown in phantom. The press ring 93 can then be pushed to the longitudinal axis on the combination of the coupling sleeve 101 and tube end 108 transversely. Due to the spring action of the tension cords 97 lie the cheek plates 94, 95 on the circumference of the coupling sleeve 101, and even here only with the outer transverse edges. Then, the driving device 103 such recognized that the upper arms 107 of the drive lever 104, the clutch 102 approaches the outer side behind grasp how this can be seen in FIG. 1 The drive lever 104 and the arms 106 are then spread in the manner described above, so that the tension straps 97 are pressed together at their free ends. This has the consequence that the coupling sleeve 101 and the tube end 108 are radially compressed, which move the lower cheek plates 95 automatically in the circumferential direction, namely the lower left cheek plate 95 clockwise and the right lower cheek plate counterclockwise. This continues until the end faces of the cheek plates 94, 95 with each other come to rest, the rubber springs are compressed 98th This situation is shown in FIG. 2

The pressing tool 92 is functionally formed similarly to the press tool 91. It also has a press ring 109, having three press jaws 110, 111 of the same arc length. The upper cheek plate 110 is fixedly disposed at a Preßbackenträger 112, while the bottom two pressing jaws are guided 111 circumferentially displaced to Preßbackenträgern 113th The lower Preßbackenträger 113 are articulated via pivot joints 114 to the upper Preßbackenträger 112th

The lower cheek plates 111 are provided at their outer peripheries to notches 115, bordering the axially displaceably mounted in the lower Preßbackenträgern 113 pins 116th These pins 116 are spring biased by compression springs 117 toward the notches 115th The pins 116 and the notches 115 are arranged so that the pins 116 are committed to providing the lower cheek plates to move in the circumferential direction 111 against each other, the illustrated right lower cheek plate 111 clockwise and the cheek plate not shown here counterclockwise. Stops shown here unspecified ensure that the lower cheek plates 113 can not be moved further in these two directions over a certain maximum dimension beyond.

At the free ends of the lower Preßbackenträger 113 vertically above the plane of the drawing drive pins 118 are arranged, which take over the function of the coupling tabs 102 at the pressing tool 91st On this drive pin 118, the driving means shown in the left half of the figures 1 and 2 can be set 103 by the upper arms 107 of the drive lever 104 is applied to the outer sides of the drive pin 118th

The pressing tool 92 is handled in the same manner as the pressing tool 91. First, the pressing ring 109 via the coupling sleeve 101 and the tube end 108 is transversely slid to its longitudinal axis, wherein the two lower Preßbackenträger 113 open, that is, are pivoted outwardly, as dot-dashed lines is indicated. Thereafter, the lower Preßbackenträger 113 are brought to bear against the outer periphery of the coupling sleeve 101. The aforementioned stops for limiting the movement of the lower cheek plates 111 are circumferentially arranged so that arise in contact with the coupling sleeve 101 of the same size column 119, 120 between the faces of the cheek plates 110, 111th

Through further spreading of the lower arms 106 of the drive lever 104, the lower cheek plates are pivoted 113 inward, move the lower cheek plates 111 automatically in the circumferential direction M, namely the illustrated right cheek plate 111 counterclockwise and the left, not shown here, press jaw in clockwise. This continues until the end faces of the pressing jaws 110, 111 come to rest on the pressing end. This state is shown in the right half of Figure (2).

Of course, the dies can be 91, 92 formed in one piece, ie, the drive device 103 may be connected via a corresponding housing part with one of the cheek plates 94, 95 110, 111th In this case, the respective press jaw 94, 95, 110, 111 would be similar to an abutment, wherein the cheek plates 94, 95, 110, 111 move in the pressing continuously towards the center of the baling chamber in the closed state of the die 91, the 92nd This can provide some of the lower cheek plates 95, 111, the fixed position on the pressing tool 91, 92 are arranged, the function of the abutment engaged cheek plate 95, his 111th In this case, it requires only a drive lever 104 for contracting the cheek plates 94, 95, 110, 111th