Hinged join prodn. between to sections - by co-extruding two opposite semicircular sections and one hinge strip running S-fashion between opposite ends of those sections

摘要

A hinged joint between two sheets or panels is produced where the prod. has at least two hinges, each of which is semi-circular or arc-shaped in cross-section; these meet along a line contact and are joined together to form an S-section running from the end of one semi-circle to the diametrically opposite end of the other semi-circle. Both semi-circular shapes and the hinge strip itself are produced as one piece in a single operation. The semi-circular materials are pref. unplasticised PVC and are coextruded with a plasticised PVC hinge strip in the one extrusion process. More specifically the finished assembly has two semi-cylindrical bodies with bent-in ends to fit on to e.g. a door and wall respectively. They are joined together by hinge strips, each of which forms an S-shape, running from one end of one body to the opposite end of the other body. The two strips run in opposite directions to prevent each other from opening up when the bodies turn. In production the two types of PVC for the bodies and hinges are coextruded. Two barrels express their polymers together out through one common die from their separate flow bores i.e. the hard and soft PVC streams unite shortly before reaching the die. To produce the mirror-image hinges their sections are turned through 180 deg.. ADVANTAGE - The process is simple. The prod. is made in one operation by the use of one main and one subsidiary extruder for the semi-circular sections and hinge strip respectively. The method is thus economical and can produce any desired length.