Cable drawn mast ladder - has link longerons and rungs, each with central runner engaging vertical track

摘要

The vertically extending ladder for a ship's mast (4) slides up a vertical support when being extended. It has rigid 'rung' bars (3) joined by cord longerons (9) each rung (3) having a centrally projecting runner (2) which engages a vertical track (1). A cable (13) over a pulley (12) at the top may be used to pull the ladder up into its extended position. The track (1) may be a continuous dove-tail section channel and the runners (2) of a reciprocal form, or alternatively, the track and the runner may be of a slotted box and a 'T' section. In a further alternative form, the mast has a 'T' section fitting into a slotted box section projecting from the back of each rung. The cord longerons (9) may be in short lengths corresponding to that of a run interval. Rings (8) projecting from opposite sides of each rung (3) are used to fasten each length (9).