Prodn. of window in casing wall - by making hole with e.g. annular groove in wall, inserting O=ring in groove, and injection moulding window into groove and flush with surfaces

摘要

The wall of a casing and partic. one of a box to hold electrical or electronic components, is produced with a hole and an injection moulded inspection window over that hole. The rim of the hole has a circumferential groove or shoulder, in or on which it holds an elastic sealing ring; the window is then injected so that it lies against the ring and compresses it in doing so. Pref. the box has a cover (2) held on by four corner screws (3). At its centre the cover (2) has a circular hole (2c) with a circumferential groove (2a) running all round. This groove (2a) holds an O-ring (5). The inspection window (4) is injection moulded in position so that its faces are flush with those of the cover (2). The window (4) has a circumferential rib which fits against the O-ring (5) and thus fills the rest of the groove (2a). This window (4) is injection moulded in position; when it subsequently shrinks it is still sealed by the ring (5). ADVANTAGE - The method makes a tight joint between the seal and window, even if the window is made of a different material from that of the casing itself.