the best effect the thread eyes 32 are preferably located centrally in front of the third thread guide device 30 and in a plane parallel to the plane in which the thread guide slots 31 are situated furthermore the thread eyes 34 of the second thread guide device 29 are preferably situated opposite the centres of the thread guide slots 31 clearly the second thread guide device 29 does not necessarily have to consist of the above mentioned plate 33 and the thread eyes 34 in a simpler embodiment the second thread guide device 29 can also be formed by the thread eyes 36 of the weft detector 35 as shown in fig1 however it is recommendable for an arrangement as shown in fig6 to be used since the distribution of the weft threads 8a to 8d between the first and second thread guide devices 28 and 29 is then always symmetrical fig1 to 18 show embodiments in which as indicated in the preamble arrangements are made to compensate fully for the lengthening of the path followed by the weft threads 8 which normally occurs when the assembly 27 rotates such that no sagging of the weft threads 8 occurs when the assembly 27 rotates back into its original position the particular feature of this arrangement is that the device includes a means 39 which converts the rotation motion r of the assembly 27 into a translation motion t essentially in the direction of the axis of rotation 9 for this purpose the above mentioned frame 10 is constructed so that it can not only rotate but also be displaced for example along the shaft 40 extending in the direction.