| 摘要 |
The pantographs (3a) at their free end are interconnected by a bar (7a), which together with the sill element (9) forms such a kinematic system that turning round the bar (7) pulled at its crank forces the catching element (7a) to turn and to move in relation of the sill element (9), releasing by this the ladder (3) from its lock and enabling to expand the ladder (3). The sill element (9) has in its cross-section parallel to side element of the ladder (3) a triangular profile and has an abutting surface on the side of the hinges connecting the flap (2) with the hatch frame (1), which surface passes arch wise into an adjoining sliding surface forming an acute angle with the surface of the flap (2). |
