Abstract: A lock mechanism comprising a mounting part, a manually operable part, a retaining part and a stabilizer part, said parts being pivotally connected together as a substantially parallelogram linkage with the retaining part and mounting part located on opposed sides of such linkage; the manually operable part, retaining part and stabilizer part of the linkage being pivotable relative to the mounting part between a locking condition, in which the retaining part is intended to engage a component which is to be secured by the mechanism and further in which the operable part is substantially parallel with and lies adjacent to the mounting part, and a release condition, in which the retaining part is intended to be disengaged from said securable component; pivotal movement of the linkage between its locking and release conditions being effected by manual displacement of the operable part relative to the mounting part.