of the feeding and spooling means 3 b suitable for controlling the travel speed of the joined yarns the assembly members 7 a 7 b 7 c 7 d are therefore placed downstream of the first feeding and advance means 2 a 2 b 2 c and upstream of the feeding and spooling means 3 a 3 b 3 c it has been observed that the feeding and or spooling means 3 a 3 c and their corresponding thread guides 6 a 6 c are in the particular case of the assembly mentioned as an example unused because their respective yarns are diverted toward the feeding means 3 b and its corresponding thread guide 6 b advantageously regardless of the embodiment fig2 fig3 fig4 each individual motor 8 a 8 b 8 c 8 d of the first feeding and advance means 2 a 2 b 2 c 2 d is subjected to a variator 15 a 15 b 15 c in the embodiment shown in fig2 the feeding and spooling means 3 a 3 b 3 c 3 d are driven by a common drive member 5 the thread guides 6 a 6 b 6 c 6 d are driven by a common drive member 6 in the embodiment shown in fig3 the feeding and spooling means 3 a 3 b 3 c 3 d are each driven by an individual drive member 10 a 10 b 10 c the same applies to the thread guides 6 a 6 b.