| 摘要 |
<p>A two piece (1, 8a) rectangular collar contains a column (4) of rectangular hollow section and widely slotted on a major face, the collar (1) incorporating an "I" sectioned stub (3) which projects into the column and supports two opposed leaf sprung (20) cam shaped blocks (16a), (16b), in such a position that they bear on opposed inner column walls (12). The scotch blocks are of tapered cross section with a semi-circular nose (15) and convex outer surfaces (18), the nose bearing rotatably on a mating surface of the collar stub (3) and the outer surface bearing on the column wall (12). A blade spring (20) traverses the stubs (3) to support the scotch blocks and the arrangement thus enables the collar to slide up the column and lock against downward forces.</p> |
