| 摘要 |
A sight arrangement for a door comprises an annular body 2 with a screw thread engaged by a locking ring 3 to secure a sight transparency 6 such that when assembled there is substantially no gap between the sight transparency and the annular body and/or the ring. The ring may include opposed key indents (17, Figure 2) to tighten it into the body. Substantially incompressible, 1 mm thick rubber gaskets 11, 12 may be provided between the transparency and the body and/or ring. The body or the ring may have a flange 14 for engaging about an aperture in the door. The body and ring are preferably aluminium. The ring may be locked against rotation by a screw, peg or a spot weld. The sight transparency may be made of glass and may have a chamfer or shoulder 21 on each end for engagement by the body and the ring to locate the transparency. |
