Frames for windows and other panels

A composite section of indefinite length suitable for forming rectangular frames, said composite section comprising a first section made of rigid metal, a second section made of plastics less rigid than said metal section, first and second hook formations on said first section, both of said hook formations being spaced apart and pointing in the same direction, third and fourth hook formations on said second section, said third and fourth hook formations being spaced apart and pointing in the same direction and adapted to engage respectively in said first and second hook formations, at least one of said first and second hook formations being of tapering profile, whereby to achieve a wedging action with the co-operating third or fourth hook formation, a first abutment surface on said third hook formation, a second abutment surface on said first section, and wedging means, said wedging means comprising a strip of indefinite length adapted to be inserted between said first and second sections whereby to force said spaced-apart first and third hook formations and said second and fourth hook formations into tight play-free engagement and simultaneously bringing said abutment surfaces into tight mutual engagement.