| 摘要 |
<p>PROBLEM TO BE SOLVED: To miniaturize the posture of a ladder on housing it by forming a specified space in between a first ladder and a second ladder by an intermediate means for connecting the first and second ladders when these ladder are stretched. SOLUTION: A ladder housed in a ceiling is constituted of an upper stage unit in which handrails 31 and the upper stage ladder 28, etc., are connected by the lower frame 29 and the upper frame 29', a jointing support 8 which is slidable to the ladder 28, a lower stage ladder 2 which is slidable to the joint support 8, and a drive unit. The support 8 has no step and the ladders 3, 28 are connected by respective two guide rollers separated in the upper and lower stages. When the ladder is used. The support 8 is positioned at the side face of the stretched ladders 3, 28, and it is positioned at the side face of the stacked ladders 3, 28 when the ladder is housed. The length of the support 8 is designed so that the distance between the lowermost step of the ladder 28 and the uppermost step of the ladder 3 is almost equal to the distance of other steps, when it is used. In this way, since the upper and lower stage ladders become shorter by the length of the jointing support, the housing length can be shortened unconventionally and the number of parts can be reduced, compared with a three-stage ladder.</p> |
