| 摘要 |
The molded box (5) is eg. 6-sided, with a clip-on (7,8) end cover (6). The face-plate (9) at the other end, integral with the box, has a circular central opening (4), with a short upstanding skirt (10), intended to fit into an aperture cut in the wall-board (3) from the front, the box having been temporarily located on the rear face at approximately the correct position while the cavity covered by the board was still accessible. Spikes (13) molded on the face-plate penetrate the board, preventing rotation. A retaining ring (2) has a skirt (20), interrupted by notches (28), that fits into the box skirt. 3 equally spaced axial columns (11) inside the latter slide in semicylindrical guides (24), projecting from lugs (22) formed inside the flange on the ring face. Using 3 screws (25) passing through the ring lugs into the columns on the box skirt, the ring is tightened against the latter so that the rim of the board apertures is firmly clamped between the ring flange and the box face-plate. Access to the box interior is finally sealed off by an outer cover (30) held in place by clips (31) fitting the ring skirt's notches (28). 3 variants are described.
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