| 摘要 |
A default-immobile ladder (10) includes mobility means (12) displaceable between a ladder immobile position and a ladder mobile position in which the mobility means extends downwardly beyond the foot of the ladder and manually actuable means (32) for displacing the mobility means from the ladder immobile position to the ladder mobile position. When the manually actuable means is released, the mobility means returns to the ladder immobile position. |
