to the other along the weaving width at a set interval this only to allow cleaning activities to be carried out at regular intervals as shown in fig1 the range of possibilities can include on the one hand a combination of tubes 15 attached to the carriage 39 or similar and on the other hand tubes 15 fitted to the above support bracket 21 the compressed air source 34 may be of any type it may for example consist of a compressed air connection to an existing network of a special compressor used to this end or of a conduit system which supplies loss air the latter is schematically shown in fig1 whereby the waste or exhaust air from the cylinder 50 which moves the electrodes 51 of the warp stop motion 4 from side to side is used for feeding blowing air to the tubes 15 the electrodes 51 as described in ch 430611 and u s pat no 3 907 006 move to and fro over a short distance for example by using the cylinder 50 which via a pulse controlled valve 52 is connected to a compressed air source 53 by moving the electrodes 51 to and fro dust is shaken from between the drop wires 40 the waste air which is forced out of the non active side of the piston of the cylinder 50 is fed through a pipe 54 to the flexible tube 48 and possibly to the flexible tube 35 obviously the to and fro motion of the electrodes 51 must coincide with.