Abstract:
The invention relates to a pipe coupling having a sleeve-shaped outer body for accommodating a sealing arrangement and at least one pair of clamping elements, which is arranged adjacent to one side of the sealing arrangement inside the sleeve-shaped outer body and serves to clamp the end of an inserted pipe in place, in which case the pair of clamping elements can be restrained against the end of an inserted pipe transversely to the axis of the pipe coupling via a clamping screw passed through the sleeve-shaped outer body and is pressed apart by of a spring, and the clamping elements are guided in the restraining direction in the sleeve-shaped outer body.

Description:
TECHNICAL FIELD 
     The invention relates to a pipe coupling as can be used for the tight connection of two pipe ends of an, in particular metallic, pipeline. 
     BACKGROUND OF THE INVENTION 
     German Patent DE 197 19 066 C1 discloses a pipe coupling which comprises a sealing sleeve which accommodates a seal and is arranged inside a supporting body, the supporting body, at least adjacent to one side of the sealing sleeve, supporting locking elements for one end of an inserted pipe, and these locking elements can dig into the inserted pipe while being raised in the radial direction when extension stress occurs. The locking elements are rectangular clamping plates, which are supported on the supporting body and are preloaded in the extension direction of the pipe via springs supported on the supporting body. Here, the clamping plates are accommodated by the supporting body in such a way that they can be pushed out, the supporting body being formed in its center part from axially extending lugs. This construction is relatively complicated with regard to the number of components and the preassembly as well as the final assembly when coupling pipes. 
     Furthermore, German Patent DE 44 28 570 C1 discloses a pipe coupling in which a relatively complicated connecting socket is provided, which is to be made as a cast part, has inner grooves, requiring internal machining, for accommodating sealing collars and is provided with through holes transversely to the longitudinal axis, the through holes serving to accommodate clamping units. The latter may consist of a clamping screw and two locking elements which can be adjusted with the clamping screw and are in the form of clamping wedges or sleeves which have cutting ribs and can be restrained against the pushed-in pipe via the clamping screw. However, the clamping units, if they were to be preassembled, would be displaceable in the through holes and could then hinder the insertion of the pipe. In this respect, this pipe coupling is also complicated and difficult to assemble. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a pipe coupling which can be produced in a preassembled state with little outlay. A further object of the invention is to provide a pipe coupling which is easy to assemble. 
     The subject matter of the invention is therefore a pipe coupling having a sleeve-shaped outer body for accommodating a sealing arrangement and at least one pair of clamping elements, which is arranged adjacent to one side of the sealing arrangement inside the sleeve-shaped outer body and serves to clamp the end of an inserted pipe in place, in which case the pair of clamping elements can be restrained against the end of an inserted pipe transversely to the axis of the pipe coupling via a clamping screw passed through the sleeve-shaped outer body and is pressed apart by means of a spring, and the clamping elements are guided in the restraining direction in the sleeve-shaped outer body. 
     Owing to the fact that a sealing sleeve containing a seal is accommodated in the preassembled state as an appropriate construction unit by a sleeve-shaped outer body, an independent, pressure-absorbing sealing unit facilitating the preassembly is formed. Owing to the fact that at least one pair of locking elements pressed apart by a spring and in the form of clamping elements is accommodated on the inside by the sleeve-shaped outer body, and this pair of locking elements can be restrained against the inserted pipe end transversely to the axis of the pressure coupling via a clamping screw passed through the outer body, the locking elements being guided in the restraining direction in the outer body, the entire pipe coupling can be preassembled from relatively few parts, in which case the locking elements also does not impair the actual assembly on account of the spring located in between, since the pipes to be connected can be pushed from here unhindered into the pipe coupling, since the pairs of locking elements are arranged so as to be self-centering by the spring relative to the pipe. In addition, during the coupling, the locking elements are pressed outward against the outer sleeve by the respective pipe end and are thereby additionally clamped, this action being intensified by internal pressurizing of the pipes. 
     Further objects, advantages and embodiments of the invention will become apparent from the following detailed description and accompanying drawings. 
     The invention will now be described by way of example with respect to preferred embodiments as shown in the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an exemplary embodiment of a pipe coupling in axial section. 
     FIG. 2 shows an end side of the pipe coupling of FIG. 1 in partial section. 
     FIG. 3 shows an embodiment of a clamping unit as provided in the case of the pipe coupling of FIG.  1 . 
     FIG. 4 shows a further embodiment of a pipe coupling in axial section. 
     FIG. 5 shows the pipe coupling of FIG. 4 in a view corresponding to FIG.  2 . 
     FIG. 6 shows a further embodiment of a clamping unit as provided in the case of the pipe coupling of FIG.  4 . 
     FIG. 7 shows a detail of an additional embodiment of a pipe coupling in axial section. 
     FIG. 8 shows an embodiment of a clamping unit as provided in the case of the pipe coupling of FIG.  7 . 
     FIG. 9 shows a further exemplary embodiment of a pipe coupling in axial section. 
     FIG. 10 shows an additional embodiment of a pipe coupling in section. 
     FIG. 11 shows a section along line XI—XI of FIG. 10 without inserted sealing collar. 
     FIG. 12 shows an end view of the pipe coupling of FIG. 10 in partial section. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The pipe coupling shown in FIGS. 1 and 2 comprises a sealing sleeve  1 , which is closed on the outside and the interior of which forms a sealing chamber, which accommodates a sealing collar  2  formed as a lip sealing ring. The latter has in each case a sealing lip  3  on both sides at the inner circumference and a central stop ring  4  which extends radially inwards, is surrounded by supporting shoulders and is intended for two ends, to be accommodated by the pipe coupling, of pipes  5  to be connected, the inside diameter of the stop ring  4  being greater than or equal to that of the pipes  5 . 
     The sealing sleeve  1  carrying the sealing collar  2  is inserted axially under prestress into a central position in a sleeve-shaped outer body  6  serving as housing and is thus held in the latter. 
     The outer body  6  is a relatively thin-walled sheet-metal formed part which may be formed from two half shells, for example welded to one another. On both sides in the exemplary embodiment, the outer body  6 , adjacent to the sealing sleeve  1 , has in each case two opposite bulges  7 , which are parallel to one another and the inner surfaces of which in each case form a guide for a clamping unit  8 . 
     Each clamping unit  8  comprises two clamping elements  9   a,    9   b,  which in the embodiment according to FIGS. 1 to  3  are designed as clamping wedges having cutting ribs  10  facing the circumference of the pipe  5  to be clamped in place and arranged essentially tangentially thereto. The two clamping elements  9   a,    9   b  are arranged on a clamping screw  11 , one clamping element  9   a  being adjacent to the head  11   a  of the clamping screw  11  on a thread-free section  11   b  of the clamping screw  11 , whereas the other clamping element  9   b  is screwed onto the threaded end section  11   c  of the clamping screw  11 . Located between the two clamping elements  9   a,    9   b  is a helical spring  12  (schematically indicated), which presses the clamping element  9   a  against the head  11   a  of the clamping screw  11 . 
     In the side region of the bulges  7 , the outer body  6  is provided with a passage opening  13  on one side for the head  11   a  of the clamping screw  11  and with a passage opening  14  on the opposite side for the threaded end section  11   c  of the clamping screw  11 , the passage openings  13 ,  14  having a diameter with appropriate clearance for the head  11   a  or the threaded section  11   c  respectively. 
     The pipe coupling may accordingly be preassembled as an entity. 
     The preassembled clamping unit  8  is centered and held in the outer body  6  as a result of the clamping elements  9   a,    9   b  preloaded relative to one another by a spring, the clamping screw  11  projecting slightly from the outer body  6  on both sides. 
     If a pipe  5  is pushed in, this pipe  5  is clamped in place by the clamping unit  8  by turning the clamping screw  11 , the clamping unit  8  being automatically centered relative to the pipe  5 . The length of the clamping screw  11  is expediently dimensioned in such a way that its head  11   a  is accommodated by the outer body  6  when the pipe  5  is clamped in place, as a result of which visual monitoring of the assembly is made possible at the same time. 
     The clamping units  8 , if need be, may be additionally supported on the lateral shoulders of the sealing sleeve  1 . 
     The outer body  6 , adjacent to the clamping unit  8 , may in each case expediently carry a guide ring  15  at the end faces for the pipe to be inserted, which guide ring  15 , in this exemplary embodiment, encloses the outer body  6  and can thus counteract buckling of the outer body  6  when the pipe  5  is clamped in place. 
     In the embodiment of FIGS. 4 to  6 , the clamping elements  9   a,    9   b  may also be designed as clamping sleeves, which have a conical engagement surface  16 , expediently knurled or provided with cutting ribs, for engaging with the outside of the pipe  5  to be clamped in place and if need be also a knurled engagement surface  17 , extending in the circumferential direction, for engaging with the outer body  6  in order to secure the clamping elements  9   a,    9   b  against rotation when turning the clamping screw  11 . 
     For this purpose, in the embodiment shown in FIGS. 7 and 8, the outer circumference of the clamping elements  9   a,    9   b  designed as clamping sleeves is polygonal (here hexagonal) and is in engagement with the correspondingly shaped bulge  7 . 
     In the embodiment shown in FIG. 9, the sealing collar  2 , instead of its arrangement in a sealing sleeve  1  according to FIG. 1, is mounted on both sides in each case by a supporting ring  1 ′,  1 ″ which is essentially J-shaped in section. This is a very cost-effective solution, although it requires a sufficiently rigid outer body  6 . 
     In addition, the guide rings  15  in this case, which in operation at the same time constitute supporting bearings, are clamped in place in the outer body  6 , which guide rings, on account of their rigidity, need not be secured against expanding. 
     In the embodiment shown in FIGS. 10 to  12 , in addition to a pair of clamping elements  9   a,    9   b,  in each case a wedge ring  18  is provided for a respective end of an inserted pipe  5 . The two wedge rings  18  are arranged adjacent to the sealing collar  2 , so that the latter is framed by the wedge rings  18  and the outer sleeve  6 . 
     The wedge rings  18  have an extension  19 , with which they are inserted in a rotationally locked manner into a corresponding opening  20 , opposite the respective clamping unit  8 , in the outer sleeve  6 , and they are supported on the opposite side on the outside by the adjacent wall of the clamping elements  9   a,    9   b.    
     In a region  22  of enlarged inside diameter opposite the clamping unit  8 , the wedge rings  18  have one or more wedges  21  (three in the exemplary embodiment shown), which are at a distance from one another, are arranged on the inside of the wedge rings  18  and are formed in one piece with the wedge rings, the cutting edges of the wedges  21  lying virtually on the inside diameter of the wedge rings  18 . When the clamping units  8  are tightened, they also at the same time press the respective end of an inserted pipe  5  against the wedges  21 . 
     In this exemplary embodiment, the guide rings  15  are provided with passage openings  23  for corresponding axial webs  24  of the outer sleeve  6 , the webs  24  being caulked after the assembly. 
     Although the invention has been described in some detail by way of illustration and example, for purposes of clarity and understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the invention.