Locking device for a thrust-secured plug connection of pipes

The invention concerns a locking device (7) for a push-in connection with retaining system for pipes (1, 2) provided with an insertion end which can be introduced with a degree of radial play into the sleeve end of an adjacent pipe. The sleeve end is provided with an annular sleeve chamber (6) with a stop surface for locking elements arranged in the sleeve chamber and with at least one opening situated at the front end, open towards the sleeve chamber and divided by a central ridge (11), for introducing the locking elements into the sleeve chamber. To ensure that the locking elements can be fixed to the sleeve end, the locking elements should be joined together to form a flexible strip and closure elements which can be tightened across the ridge should be provided at the strip ends.