Device for coupling wear pieces to the receptacle tools of a public works machine

A device for coupling linkage between wear pieces at ends of receptacle tools in use on machines, comprising a tooth fitting onto an adapter nose and coupled by a key, the adapter nose having a zone with a transverse vertical or horizontal cut-out for the key to pass through and defining a transverse border forming an abutment surface, wherein the tooth has, at its rear end away from a scraping point, an enveloping skirt covering the adapter nose beyond the zone through which the key passes, said skirt having a shaped configuration connecting to a rectilinear flat return wall, comprising a bordering ridge, and wherein said return wall is established in a width of the skirt and corresponding to passage and positioning of the key, and wherein located adjacent ends of said return wall, and in a thickness of the skirt, are openings for the key to pass through with no abutment function in an operating situation and performing a guidance and abutment function exclusively when the key is inserted or removed, and wherein the key comprises two components movable one relative to the other, in a transverse direction, said key having, on each of these components, contact and opposing contact abutment zones, on the one hand, abutting against the abutment surface of the adapter nose and, on the other hand, against the return wall, at the place of its bordering ridge, in a space situated between the openings for the key to pass through.