Metal frame assembly for windows or doors

An insulated metal frame assembly for windows and doors comprising at least two opposed metal sections which are joined together by an insulating strip provided with a strut and with a channel to receive a seal, said channel being formed by a pair of clamping strips projecting out from said strut of said insulating strip to form an undercut groove and said seal being provided with a hammer-head-shaped projection having a groove which receives the pair of clamping strips such that the hammer-head-shaped projection of said seal is received in said undercut groove, wherein each of said at least two opposed metal sections is provided with a pair of spaced apart wedge-shaped strips defining substantially U-shaped undercut grooves in each of said sections and said strut is provided with heads on its ends which are adapted to engage the wedge-shaped strips on said at least two opposed metal sections.