| 摘要 |
The bolt (14a) plugged through the upper tube (13) is supported, in the load-bearing position, on two supporting surfaces (23b) which are located above a displaceable plate (20). By displacing the plate, the plug-in bolt falls downwards onto said plate, as a result of which the support is released. Displacement of the plate is, however, prevented by a locking means in the form of a rectilinear portion (14c) of the plug-in bolt, which is located beside two cams (23c). It is only when the locking bar (14c) is pivoted some way upwards, so that the cams become free, that the plate can be displaced. <IMAGE>
|
