Mitred joint for frame with hollow sections

摘要

A window frame etc. is constructed from hollow plastics or metal sections. The corner joints of the frame are formed by blocks (1) of plastics, which are inserted in the ends of the hollow section.Each block has one end face cut obliquely at an angle of 45 deg, whilst longitudinalslits (6) extend from the opposite end face (5) along the side faces(8).The block has a central axial hole (7) for a bolt, which engages an expander cone fitted in the end face. The block is inserted in the hollow section and retained by expanding the inserted end. The oblique end face is then welded to the oblique end face of a second block inserted in a second hollow section