Abstract:
In connection with an arrangement for fastening a corrugated pipe ( 11 ) on an essentially hollow-cylindrical connector ( 12 ), at least one spring leg ( 15 ), which extends at a radial distance from and in a longitudinal direction to the connector ( 11 ) and has a retaining lug ( 18 ) radially projecting toward the latter, is formed on the connector ( 12 ), and an annularly-shaped clamping element ( 20 ) is placed on the outside around the corrugated pipe ( 11 ) pushed onto the connector ( 12 ), which generates a radial clamping force directed toward the corrugated pipe ( 11 ) on the at least one spring leg ( 15 ), for providing a dependable and simple connection technique (FIG.  2 ).

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to an arrangement for fastening a corrugated pipe to an essentially hollow-cylindrical connector, in particular in connection with fuel-delivery units of motor vehicles. 
     Such corrugated pipes, which as a rule are flexible, are used in fuel-delivery units of motor vehicles as connecting lines between the pressure connector of an electric fuel pump integrated into a filter bowl and a connector formed in a tank flange for the delivery line leading to the internal combustion engine (DE 44 44 854 A1 or DE 42 24 981 A1). To achieve a pressure-resistant fastening between the connector and the corrugated pipe, the connector has a so-called Christmas tree profile on its exterior jacket there, onto which a specially shaped straight end element with auxiliary grooves cut therein is pushed. The shaped end element of the corrugated pipe is interlocked with the Christmas tree profile by means of the auxiliary grooves, so that the connection cannot be loosened even under delivery pressure. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention an arrangement for fastening a corrugated tube is proposed, which has a connector with spring legs and a clamping element generating a radial clamping force directed toward the corrugated pipe on the at least one spring leg, and the connector with the spring legs are formed of one piece on a flange of a fuel tank, while the connector constitutes a pipe section protruding from the tank flange. 
     The fastening arrangement in accordance with the invention of a corrugated pipe on a connector has the advantage that it is possible to omit both the Christmas tree profile on the connector, which is complicated from the viewpoint of injection molding technology, and also the special contact pressure geometry of an end element of the corrugated pipe. Because of this, the corrugated pipe can be produced without an end element in the form of a so-called “endless corrugated pipe”, and can be cut to the required size during assembly. This entails cost advantages both in the manufacture and the storage of the corrugated pipe, which no longer needs to be stocked in different lengths and can now be stored in a rolled-up state as a space-saving roll. It is possible to produce the spring legs with retaining lugs on the connector by means of forced removal with cost-efficient plastic injection molding tools without elaborate transverse slides, so that a cost advantage in comparison with the Christmas tree profile also results here. As a whole, by means of the fastening arrangement in accordance with the invention a very cost-effective and qualitatively outstanding connection technique between the corrugated pipe and the connector is achieved, with the possibility of very simple and cost-saving disassembly when service is needed. 
     By means of the measures recited in the further claims, advantageous further developments and improvements of the measuring device disclosed in claim  1  are possible. 
     In a preferred embodiment of the invention, a seal ring in the form of an O-ring is inserted between the outer jacket of the connector and a crest of the corrugated pipe. The corrugated pipe is totally pressure sealed in respect to the exterior jacket of the connector by means of the annularly-shaped clamping element, which can be designed as a hose clamp, cable clamp or sliding sleeve and exerts a radially directed clamping force on the spring legs and, via their lugs, which engage the troughs of the corrugated pipe, on the corrugated pipe and the connector. 
     In accordance with an alternative embodiment of the invention, for forming the spring legs a ring, which surrounds the connector coaxially at a radial distance, is provided with longitudinal slits extending from a closed annular collar as far as the free front end of the ring. In this case the O-seal can also be inserted between the inner ring surface of the annular collar supporting the spring legs, which extend axially outward, and a trough of the corrugated pipe. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in greater detail in the following description by means of exemplary embodiments represented in he drawings. Shown are in: 
     FIG. 1, by means of sections a fastening arrangement of a corrugated pipe on a partially cut connector at a time prior to the termination of assembly, 
     FIG. 2, the same representation as in FIG. 1 after assembly has been finished. 
     FIG. 3, the same representation as in FIG. 2 in accordance with two further, alternative exemplary embodiments, 
     FIG. 4, the same representation as in FIG. 1 in accordance with a fourth exemplary embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The fastening arrangement of a corrugated pipe  11  on a connector  12  represented in longitudinal section in FIGS. 1 and 2 is provided in a fuel delivery unit for motor vehicles such as described, for example, in DE 44 44 854 A1. The hollow-cylindrical connector  12  is made of one piece with a tank flange  13  of plastic, which is placed on the top of a fuel tank. Here, the hollow-cylindrical connector  12  constitutes the portion, extending into the interior of the tank, of a connection  14  for a fuel delivery line leading from the fuel tank to the internal combustion engine of a motor vehicle. The corrugated pipe  11  makes the connection with the pressure side of an electric fuel pump arranged in the fuel tank, and is connected there with the fuel pump. In a known manner, the flexible corrugated pipe has a multitude of successively arranged crests or rises  111  and troughs or depressions  112 , which extend in an annular or helical form over the circumference of the corrugated pipe  11 . For reasons of removal following the injection molding process of the tank flange  13 , the hollow-cylindrical connector  12  can also be shaped slightly conically, as represented in FIGS. 1 to  4 . 
     A plurality of spring legs  15 , which are located offset in respect to each other on a graduated circle, is arranged at a radial distance from the connector  12  and essentially extends parallel with the connector axis and are formed as one piece on the connector  12 , or respectively the tank flange  13 . As in FIG. 1, these spring legs  15  can be made as individual elements, which project at right angles away from the interior surface of the tank flange  13 , or they can also be provided in that—as represented in FIG.  4 —a cylinder-shaped ring  16 , which is formed on the tank flange  13  and coaxially encloses the connector  12 , is provided with longitudinal slits  17 , which start at the free end of the ring  16  and extend as far as a closed annular collar  161 . All spring legs  15  have been made the same length and, at their free end, support retaining lugs  18  which project radially toward the connector  12  and are shaped in such a way that they are able to engage interlockingly to a large extent a trough  112  of the corrugated pipe  11 . The retaining lugs  18  are made of one piece with the spring legs  15  and are already formed during the injection molding process of the tank flange  13 , the same as the connector  12  and the spring legs  15 . 
     To create a fastening arrangement, the corrugated pipe  11  is cut off in the required length from a coil of corrugated pipe and one end of it is pushed onto the connector  12 . For the liquid-sealed connection of the fastening arrangement, an O-shaped seal ring  19  is inserted into a crest  111  in the interior of the corrugated pipe  11 —as sketched in FIG.  2 —and is pushed together with the corrugated pipe  11  onto the connector  12 . Then a clamping element  20  is placed on the outside around the spring legs  15  and a radial clamping force is exerted on the spring legs  15  by means of the clamping element  20 , because of which the retaining lugs  18  of the flexibly-elastic spring legs  15  dip into a trough  112  of the corrugated pipe  11  and press it against the exterior jacket of the connector  12 . In this way the seal ring  19  is simultaneously frictionally clamped between the connector  12  and the corrugated pipe  11 . The clamping element  20  can be designed in different ways, for example as a hose clamp or also a cable clamp. The finished fastening arrangement between the corrugated pipe  11  and the connector  12  is represented in FIG.  2 . As can be seen without difficulty, the corrugated pipe  11  is fixed in place immovably and pressure-sealed by the spring legs  15  with their retaining lugs  18  by the action of the clamping element  20 . 
     In the two exemplary embodiments of the fastening arrangement between the corrugated pipe  11  and the connector  12  represented in FIG. 3 to the left and right of the connector axis, the annularly-shaped clamping element  20  is respectively embodied as a sliding sleeve  21 , or respectively  21 ′. The sliding sleeve  21 , which can be seen on the left in FIG. 3 has a clear cross section, which conically tapers in a direction opposite the slip-on direction, so that in the course of continuously being slipped on, the sliding sleeve  21  increasingly pushes the spring legs  15  in the direction toward the connector  12 , so that their retaining lugs  18  dip into a trough  112  of the corrugated pipe  11  and clamp the corrugated pipe  11  to the connector  12  in a frictionally connected manner. In the exemplary embodiment of the sliding sleeve  21 ′ represented to the right in FIG. 3, it does not have a conical, but a cylindrical inner ring surface. Here, the spring legs  15 ′ are provided on their back facing away from the connector  12  with a wedge-shaped longitudinal rib  22 , whose radial rib height increases in a direction opposite the slip-on direction. To slip the sliding sleeve  21 ′ onto the spring legs  15 ′, the latter must be manually pressed on the corrugated pipe  11  pushed on the connector  12  until the cylinder-shaped inner ring surface of the sliding sleeve  21 ′ can be pushed past the longitudinal ribs  22 . 
     For the liquid-sealed embodiment of the described fastening arrangement between the corrugated pipe  11  and the connector  12 , the O-shaped seal ring  19  in an alternative exemplary embodiment in accordance with FIG. 4 is not arranged—as represented in FIG.  2 —between the connector  12  and the corrugated pipe  11 , but between the corrugated pipe  11  and the annular collar  161  of the ring  16 , and is pressed in a frictionally connected manner in a trough  112  on the one side against the corrugated pipe  11 , and on the other side against the cylindrical inner surface of the annular collar  161 . The clamp-tightening element  20  to be pushed over the spring legs  15  is not represented in FIG.  4 . It can be designed as a hose clamp or cable clamp, as in FIG. 2, or as a sliding sleeve, as in FIG.  3 . In the same way as represented in FIGS. 2 and 3, the clamping element  20  presses the retaining lugs  20  on the spring legs  15  into a trough  112  of the corrugated pipe  11  and in the process simultaneously generates a radial contact pressure of the annular collar  161  against the seal ring  19 .