GB1486202A - Ladders - Google Patents

Abstract

1486202 Extending ladder M L AVIATION CO Ltd 19 Nov 1975 [16 Sept 1974] 40250/74 Heading E1S An extending ladder of the suspension type comprises rungs 5 connected to articulated rigid links comprising sub-links 8, 15 provided with cooperating pressure pads 13, 14. by means of a member 4 to which the sub-links are pivoted, the links being foldable to a stacked configuration in which they lie substantially horizontally on top of one another in the plane of the rungs (see Fig. 2), the hinged joints between adjacent links including interlocks each comprising a cam 2 on the end of one link 15 in the form of a sectorshaped portion centred about the pivot point 3 of that end of the link and a co-operating cam follower 10 on the end of the adjacent link 8 which bears against the cam surface (10B, Fig. 2) to prevent rotation until the upper link 15 rotates to take the cam to a position (2A in Fig. 2) in which the cam follower is beyond the end of the sectorshaped portion and is allowed to move towards the pivot point 3 thus permitting turning movement of link 18 (Fig. 2) to the vertical position (as 8 in Fig. 1) in which position the link next above it is locked in the vertical position and cannot start to turn to a horizontal position until link 8 (Fig. 1) is substantially horizontal, the links being prevented from turning past the fully extended position by pressure pads 16, 12 which cooperate with pressure pad 11 on the intermediate member 4.