| 摘要 |
1,249,781. Foldable ladders. ERNST JANNER & SOHN KG. 19 Feb., 1970 [7 March, 1969], No. 8136/70. Heading E1S. In a ladder of which both stiles are lazy tongs, each link of the lazy tongs comprising a two part bore section member 1, 1' spot welded along flanges 2, the links are pivotally interconnected at their centres by a bolt 4 passing through a bush 5 in one link and a distance piece 6 in the other, the bolt also serving to secure a tread bracket 10 and at their edges by rivets passing through by rivets IS passing through a similar bush and connecting piece. The tread bracket is also secured by a bolt 11 engaging a nut 12 welded to the inside of one of the box section halves. The links taper from the centre, towards each end. The portion of the bolt or rivet within the bush is coated with plastics. |
