Abstract: To facilitate the fixing of attachments to the side walls of scraper-chain conveyors upstanding recesses are provided in the side walls in upper regions where the upper flanges merge with the side walls. The recesses, which can be milled, open from the upper flanges and have a depth less than the thickness of the side wall upper regions. The recesses are generally U-shaped as viewed from the exterior. The recesses are enlarged or undercut internally to be deeper all round so as to provide shaped pockets which exactly match the shape of non-circular heads of threaded elements which are received therein and fill the recesses.