| 摘要 |
Holders (5) on the front plate (2) are provided for each side frame (1), each comprising a support plate (8) fixed to the front one and a pressure plate secured to it by a clamping screw (7). The gap between the plates is adjusted by the screw, and accommodates the frame end, which contains a slot for the screw, the slot extending from the frame end. The slot forms a guide for a protrusion (14) tapped to take the screw. One end of the protrusion extends into the opening (12) for the screw in the support plate. The screw bears against the support plate via its head (17) or a washer (18) between them. Ramp faces (13) can be provided on the support plate so that on tightening the screw the protrusion is pressed against the side of the slot towards the front plate. There can also be an embossed portion (8a) on the plate which is depressed by tightening the screw. |
