High pressure-resistant screw connection for pipelines or hose lines having a tapered thread

Abstract

A connecting device for pipelines or hose lines with a threaded body and with a pipe-like end piece which can be inserted into a receptacle formed on the threaded body and which can be fitted therein by means of a swivel nut screwed onto the threaded body, wherein the receptacle of the threaded body has the shape of a widening cone and the circumferential surface of the end piece that engages in the receptacle has a conical design, is characterized in that the circumferential surface ( 12 ) of the threaded body ( 10 ) that bears the external thread ( 30 ) has, in the direction of the front end of said surface, an inclined profile directed opposite to the cone of the receptacle ( 11 ), and the swivel nut ( 17 ) has, with its surface ( 18 ) bearing the internal thread ( 31 ), a profile complementary thereto, and the external thread ( 30 ) and internal thread ( 31 ) are designed as tapered threads in such a way that a radial force emanating from the tapered thread with the swivel nut ( 17 ) screwed on is directed opposite to the radial force exerted, with the connecting device mounted, by the conical end piece ( 13 ) onto the receiving cone ( 11 ) formed in the threaded body ( 10 ).

1 . A connecting device for pipe or hose lines with a threaded connection body having a bore for passing through a medium flowing through the pipe or hose line and with a pipe-like end piece which can be plugged into a receptacle constructed at the front end of the threaded connection body and can be fixed therein by means of a union nut which has an internal thread, which can be screwed onto an external thread applied on the outer circumference of the threaded connection body, and is arranged rotatably between a release position and an installed position, wherein the receptacle of the threaded connection body is constructed in the form of an expanding cone and the circumferential surface of the end piece engaging into the receptacle has a conical shape corresponding to the receiving cone constructed on the threaded connection body and tapering to the end of the end piece, wherein the circumferential surface of the threaded connection body carrying the external thread has a course in the direction of its front end which is inclined oppositely to the cone of the receptacle and the union nut has a course complementary thereto on its surface carrying the internal thread, and external thread and internal thread are constructed as tapered threads such that in the case of installed connecting device, radial force exerted by the conical end piece onto the receiving cone constructed in the threaded connection body is directed oppositely to a radial force emanating from the tapered thread with the union nut screwed on. 
     
     
         2 . The connecting device according to  claim 1 , wherein the tapered thread is constructed as a conical apex thread. 
     
     
         3 . The connecting device according to  claim 1 , wherein the tapered thread is constructed as a thread having a trapezoidal profile of its thread turns. 
     
     
         4 . The connecting device according to  claim 2 , wherein the geometry of the tooth flanks of the tapered thread is designed in such a manner that when reaching an installation position of the union nut on the threaded connection body defined by a predetermined tightening torque, during initial installation a gap remains between the tooth flanks of external thread and internal thread placed in the screwing direction and also in the respective thread root in each case as retightening reserve of the tapered thread. 
     
     
         5 . The connecting device according to  claim 1 , wherein the geometry of the tooth flanks of the tapered thread is designed in such a manner that before the installation position of the union nut defined by a predetermined tightening torque on the threaded connection body is reached, the respectively interacting tooth flanks;  of external thread and internal thread bear against one another and a gap remains in the respective thread root. 
     
     
         6 . The connecting device according to one of  claim 1 , wherein the external thread constructed on the threaded connection body and the internal thread constructed in the union nut have a mutually different thread pitch in each case. 
     
     
         7 . The connecting device according to  claim 6 , wherein the thread pitch of the external thread constructed on the threaded connection body is designed to be larger than the thread pitch of the internal thread constructed in the union nut. 
     
     
         8 . The connecting device according to one of  claim 1 , wherein the thread turns of the external thread applied on the threaded connection body and of the internal thread constructed in the union nut have a different opening angle of their tooth flanks. 
     
     
         9 . The connecting device according to  claim 8 , wherein the tooth flanks of the thread turns of the internal thread constructed in the union nut have a larger opening angle than the tooth flanks of the thread turns of the external thread constructed on the threaded connection body. 
     
     
         10 . The connecting device according to  claim 8 , wherein the tightening torque defining the final installation state of the connecting device is set up in such a manner that the end section of the threaded connection body lying between the receiving cone and the external surface  carrying the external thread is elastically inwardly pretensioned towards the end piece pushed into the receiving cone. 
     
     
         11 . The connecting device according to  claim 1 , wherein the external thread applied on the threaded connection body has a larger axial length than the internal thread constructed in the union nut. 
     
     
         12 . The connecting device according to  claim 1 ,  wherein a groove with a seal arranged therein to be constructed in the internal surface of the receiving cone of the threaded connection body accommodating the conical region of the end piece.