Abstract:
A pressed connection arrangement including a first pipe end and a connection piece configured to receive the pipe end. The connection piece has a ring-shaped receiving device and the ring-shaped receiving device includes a cutting ring and a sealing ring. A separating ring is located between the sealing ring and the cutting ring such that the separating ring holds the cutting ring at a distance from the sealing ring.

Description:
This application claims benefit of German Application 20 2004 007 291.2 filed May 7, 2004, which disclosure is hereby incorporated by reference herein. 
   BACKGROUND AND SUMMARY 
   The present disclosure relates to a pressed-connection arrangement having a connection piece. The connection piece may be made of a cold-workable material, which is constructed on a fitting or a valve and into which a pipe end can be pushed. The connection piece has a ring-shaped receiving device in which a metallic cutting ring and a sealing ring are held. 
   From German Patent Document DE 297 21 760, a pressed connection between a fitting and a metal pipe end is known. A receiving device for a sealing ring and a spaced receiving device for a cutting ring is provided on the fitting. A pipe end is pushed into the connection piece, and a radial pressing-together is then carried out in order to establish a sealed-off connection, the cutting ring providing a mechanical fixing of the pipe end. The providing of a receiving device for the sealing ring and of a receiving device for the cutting ring requires comparatively high expenditures. It is difficult to produce the connection piece by a forming method because, when the second receiving device is produced, there is the risk that the already produced first receiving device will be deformed again. In practice, corresponding connection pieces are therefore cast and subsequently finished. 
   From U.S. Patent Document U.S. Pat. No. 5,108,134, another pressed connection is known, in which a cutting ring and a sealing ring are arranged adjacent to one another on a connection piece. There is the risk that, during the pressing-together of the connection, the sealing ring may be damaged and its tightness can therefore not be guaranteed. In addition, the cutting ring is situated on the side facing the pipe end in the hydraulically guided area, so that a contamination of the piping system by the cutting ring cannot be excluded. 
   The present disclosure is related to a pressed-connection arrangement which ensures a durable sealing-off while its construction is simple. 
   The present disclosure includes a pressed connection arrangement including a pipe end, and a connection piece configured to receive the pipe end. The connection piece includes a ring-shaped receiving device including a cutting ring and a sealing ring. 
   Further, according to the present disclosure, a separating ring is provided between the sealing ring and the cutting ring, by which separating ring the cutting ring is held at a distance from the sealing ring. As a result, only a single ring-shaped receiving device has to be shaped out at the connection piece, in which receiving device the sealing ring, the separating ring and the cutting ring will then be held. The arrangement of a separating ring between the sealing ring and the cutting ring represents a simplification in comparison to the separate construction of receiving devices. By the separating ring, it is ensured that, during the pressing-together, the sealing ring is not damaged by the cutting ring, and a durable sealing-off can therefore be ensured. 
   According to an embodiment of the present disclosure; the sealing ring, the separating ring and the cutting ring are held in a prefixed manner as a preassembled unit in the essentially U-shaped receiving device before a pressing-together. In addition, the receiving device may have two inward-extending legs and the preassembled unit is thus held in a secured manner in the axial direction and cannot be lost during transport. Furthermore, the arrangement of the individual components cannot accidentally be confused. 
   The connection piece may be made of metal and produced by forming. A corresponding fitting can thereby be produced from a pipe section, in which case the receiving device can be produced by widening the pipe section. As a result, large diameters of over, for example, 50 mm can also be produced at reasonable cost. For the forming, presses and other tools known per se can be used. This simplifies the production of the connection piece which then no longer has to be produced from cast material with a subsequent surface finishing. 
   According to another embodiment of the present disclosure, the cutting ring has several cutting teeth which are arranged on a side facing the pipe end and, during the pressing-together, dig into the material of the pipe end. The cutting ring thereby offers a protection against a pulling-out of the pipe, in that the cutting teeth arranged in an inclined manner with respect to a radial direction can provide a particularly good securing of the pressed-connection arrangement. In this case, the cutting ring can be supported on the opposite side of the cutting teeth on a side wall of the receiving device, so that a pulling movement of the pipe can be diminished or absorbed by the connection piece. 
   The sealing ring can be held in the receiving device on a side facing the pipe end. As a result, the separating ring and the cutting ring are arranged on a side of the receiving device facing away from liquid, and the pipe end or piping system cannot be contaminated. 
   On its exterior side facing away from the pipe end, the separating ring has a rounded edge projecting to the sealing ring. The separating ring therefore has a set-back receiving device below the rounded edge, in which receiving device the sealing ring can be inserted during the pressing-together. The reason is that, as a result of compression of the sealing ring in the radial direction, its axial dimension becomes larger and the separating ring offers a space to the sealing ring, into which the latter can be pressed. In this case, the separating ring may also form-lockingly rest against the sealing ring and the cutting ring in the axial direction. 
   For an easy mounting, the separating ring is constructed to be closed in a surrounding manner and includes an elastic material, such as a plastic material, and can be inserted into the receiving device of the connection piece by a slight elastic deformation. 
   Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION THE DRAWINGS 
       FIG. 1  is a sectional lateral view of an embodiment of a pressed-connection arrangement, according to the present disclosure. 
       FIG. 2A  is a plan view of the cutting ring of the pressed-connection arrangement of  FIG. 1 . 
       FIG. 2B  is a cut-a-way view taken along line B-B of  FIG. 2A . 
       FIG. 3A  is a sectional view of an embodiment of a cutting ring, according to the present disclosure. 
       FIG. 3B  is a sectional view of an embodiment of a cutting ring, according to the present disclosure. 
       FIG. 3C  is a sectional view of an embodiment of a cutting ring, according to the present disclosure. 
       FIG. 4  is a sectional view of the separating ring of the pressed-connection arrangement of  FIG. 1 . 
       FIG. 5A  is a sectional view of an embodiment of a separating ring, according to the present disclosure. 
       FIG. 5B  is a sectional view of an embodiment of separation ring, according to the present disclosure. 
   

   DETAILED DESCRIPTION 
   As shown in  FIG. 1 , a pressed-connection arrangement  1  comprises a fitting or connection piece  2  which may be made of a metal, such as copper, steel or another metal alloy. A first pipe end  3 , which may also be made of metal, is inserted into the connection piece  2 . It is conceivable that the pipe end  3  may be made of a composite material which is then reinforced, for example, by a supporting sleeve (not shown). The pipe end  3  can be pushed into the connection piece  2  up to a stop  4  which is formed by a slight radial tapering of the connection piece  2 . 
   A receiving device  5  is constructed on an end side of the connection piece  2 , which receiving device  5  has a diameter which is enlarged in comparison to a remaining portion of connection piece  2 . The receiving device  5  has an essentially U-shaped cross-section as well as an end-side leg  7  and a leg  6  facing the remaining portion of connection piece  2 . 
   A prefixed or preassembled unit including a sealing ring  8 , a separating ring  9  and a cutting ring  10  is arranged in the receiving device  5 . These rings  8 ,  9 ,  10  are secured in an axial direction by the legs  6  and  7  and cannot accidentally fall out of the connection piece  2 . 
   The cutting ring  10  has diagonally inward-projecting cutting teeth  11  which engage, by a pointed edge, as suggested at reference number  12 , in the material of the pipe end  3 . The separating ring  9  may be made of a plastic material and is constructed to be closed in a surrounding manner and is spaced away from the cutting ring  10 . The separating ring  9  may be made of metal, such as steel, and the sealing ring  8  may be made of rubber. The separating ring  9  has a smaller radial dimension than a gap between the pipe end  3  and a wall of the receiving device  5 , so that, during a pressing-together, the separating ring  9  is deformed only slightly. 
   During the pressing-together, the receiving device  5  is pressed in a radial direction onto the pipe end  3 , the cutting teeth  11  digging into the material of the pipe end  3 . Furthermore, the sealing ring  8  is pressed against the pipe end  3  for a durable sealing. In this case, the sealing ring  8  is pressed in a form-locking manner against the separating ring  9 . In addition, the leg  7  of the receiving device  5  is pressed against the pipe end  3 . In this case, the leg  7  is inclined slightly inward, and a surrounding edge  35  faces the pipe end  3  which, after the pressing-together, can also rest on the pipe end  3 . The cutting ring  10  is supported in the axial direction at least on the leg  7 . 
     FIGS. 2A and 2B  show the cutting ring  10  having a plurality of cutting teeth  11  distributed over a circumference, between which cutting teeth  11  gaps  14  are provided. The cutting ring  10  has a ring-shaped construction but has an interruption shown as an opening section  13 . The cutting ring  10 , which may be made of metal, can be pressed together in order to insert it into the receiving device  5 . 
     FIG. 3A  is a cross-sectional view of an embodiment showing a modified cutting ring  10 ′. The cutting ring  10 ′ has two radially inward-projecting legs  20  on which cutting teeth  21  are formed so that, during a pressing-together on a rear side  22  in a radial direction, the cutting teeth  21  on both legs  20  dig into the material of the pipe end  3 . 
   In the case of the embodiment illustrated in  FIG. 3B , a cutting ring  10 ″ is provided. Cutting teeth  25  are formed which project in a radial direction and, when viewed in an axial direction, are arranged eccentrically. 
   In the embodiment of a cutting ring  10 ′″, illustrated in  FIG. 3C , cutting teeth  26  are provided which project diagonally to an inside and which are constructed to be inclined by approximately 40 to 50° with respect to a radial direction. During a pressing-together of the cutting ring  10 ′″, the pipe end  3  is secured in the axial direction. 
     FIG. 4  is an enlarged sectional view of the separating ring  9 . The separating ring  9  has an essentially T-shaped construction. On an outer circumference, separating ring  9  has rounded edges  30  projecting in an axial direction, so that, on a radial interior side of the edges  30 , a receiving device  31  is formed. The separating ring  9  may be made of an elastic plastic material, such as POM, or another suitable material. 
     FIG. 5A  illustrates an alternative embodiment, shown as a separating ring  9 ′. On one side, the separating ring  9 ′ has a receiving device  32 , in which the sealing ring  9 ′ can be form-lockingly placed in a not pressed-together condition. Otherwise, the separating ring  9 ′ is essentially constructed in a disk shape and requires a minimal amount of space. 
   The separating ring  9 ″ illustrated in  FIG. 5B  has an essentially triangular shape and a sloped edge  33 . A sealing ring  10  may be provided on this edge  33 , which sealing ring  10  can be pressed into a cavity formed between the edge  33  and the pipe end  3  during a pressing-together. 
   For establishing the pressed-connection arrangement  1 , the connection piece  2  is first produced by forming. For example, by pressing and pressing devices, an elevation is produced at which a leg  7  is bent away for producing the receiving device  5 . Subsequently, the unit, including the sealing ring  8 , the separating ring  9  and the cutting ring  10 , is mounted into the receiving device  5 . At a construction site, a pipe end  3  is then pushed into the connection piece  2  and the receiving device  5  is pressed together in the radial direction. 
   It is within the scope of the present disclosure that the geometry of the cutting ring  10  and of the separating ring  9  may vary from that disclosed herein. In addition, other types of materials may be used to construct the rings  8 ,  9  and  10 . 
   Although the present disclosure has been described and illustrated in detail, it is to be clearly understood that this is done by way of illustration and example only and is not to be taken by way of limitation. The scope of the present disclosure is to be limited only by the terms of the appended claims.