feed arm 9 in a more detailed aspect of the invention there is further provided to the subchassis running rail and the subchassis 5 an adjusting device for adjusting the space between the heald feed arm and the heald feed arm in accordance with a mesh of a reed upon start the heald feed length adjusting device is composed of the abutting part of the shaft and an adjusting thread element formed of a male thread part coupled to the abutting part and a female thread part supporting the male thread part so that the heald feed length is adjusted by means of the thread parts in accordance with a mesh of the reed in fig3 there is shown to hammer 26 is provided to a protrusion which is provided to a protrusion 25 which is provided to the shaft 14 at a position counterclockwise from the coupling position of the threading arm 17 as viewed in front thereof a hammer 28 is provided to a protrusion 27 which is provided at a position counterclockwise from the coupling position of the heald feed arm 19 as viewed in front thereof while a spring 29 for pushing the protrusion 27 upward so as to urge the shaft clockwise as.