| 摘要 |
A pneumatic damper (12a, 12b, 12c, Figs. 1 and 4) for a ladder with telescopically collapsible stile sections, the damper having a plug 14 for closing the lower end of an upper stile section (10b, Fig. 4) and a seal 22 formed by discontinuous strip 16, formed from a linear extrusion. The strip is inserted into a circumferential groove 20 in the plug, the strip being cut to a length dependent on the perimeter of the groove. The seal contacts and is retained in the groove by the inner surface of a lower stile section (10c, Fig. 4). During collapse of the stile sections, the upper section acts as a piston to compress air in the lower section. The difference between the length of the strip and the perimeter of the groove may be chosen depending of the desired degree of damping. The strip may include a flange 24 received in the groove and may have a downwardly extending skirt 22. |
