Abstract: There is described a device for interlocking together two adjacent metal frames from two different levels in a "glass skin", fitted on the framework of a building, whereon said frames are mounted either rigidly or flexibly, the components of said device having to be mounted on two frame sections which are horizontally adjacent in mounting position, which is comprised on the one hand of a male part integral with a section from the one frame, and on the other hand of a female part integral with a section from an adjacent frame which is mounted in use position, in an adjacent level, the female part having a lengthwise recess extending in mounting position, in parallel relationship with the general plane of the frame under consideration, in such a way that under the action of a translation movement of the one frame relative to another one, made in that general plane both said frames lie in, the male part is free to perform a translation and/or rotating movement relative to the female part, while both adjacent fra