shown in fig2 in which the array of the auxiliary air guide elements 3 is supported at its lower end by a slide bar 15 extending in the direction of weft insertion a number of inclined grooves 25a are formed in the front face of a slay 25 holding the array of the air guide elements 10 and the slide bar 15 is fixed atop a plurality of guide bars 16 slidably received in the inclined grooves 25a which extends normal to the direction of weft insertion the lower ends of the guide bars 16 are coupled to each other by means of a lateral pin 17 a bifurcate lever 18 is pivoted at its apex to a lateral pin 19 fixed to the side face of slay sword 21 which coupled the slay 25 to a rocking shaft 23 of the loom the distal end of the upper branch 18a of the bifurcate lever 18 a cutout in which an appropriate longitudinal section of the lateral pin 17 is received the distal end of the lower branch 18b of the bifurcate lever 18 rotatably carries a roller 20 which is received in an cam slot 70 formed in a plate 7 fixed to the framework f of the loom as the slay.