GB2183710A - Ship's ladder - Google Patents

Abstract

An access ladder which is particularly suitable for affording access to the interior of a ship's hold or other storage container comprises a first platform (7) for mounting horizontally against a generally vertical bulkhead, a first ladder section (4) pivotally mounted on said first platform, a second platform (9) pivotally mounted on the other end of the first ladder section, a second ladder section (5) pivotally mounted on the second platform, and lifting cable means (16) for raising and lowering the first and second ladder sections and the second platform relative to the first platform. The second platform may be maintained level by pivotally linking a side rail (12) on the first ladder section to side rails (14, 15) on the two platforms. The second platform may be reversibly attached to the adjacent bulkhead when the ladder is lowered, thereby stabilising the ladder in use. <IMAGE>

Description

SPECIFICATION Improved Access ladder The present invention is an improved ladder of a type which is particularly suitable for affording access to the interiorofa ship's hold orotherstorage container. It will be described particularly in the context of access to ships' holds.

For many years, access from upper deck level to the bottom of a hold has been provided by means of vertical ladders permanently secured to the bulkhead. However, the development of larger bulk carriers with increasingly deep holds has led to the view that fixed vertical ladders are no longer sufficiently safe for this purpose.

Hold access ladders have therefore been developed which comprise fixed platforms secured to the bulkhead and linked by inclined ladder sections running sideways-on to the bulkhead. An important disadvantage of such ladders is thatthey consist of a fixed structure projecting laterally further into the hold than a conventional vertical ladder and thereforevulnerableto damage by unloading grabs.

Such damage entails costly repair work.

Thusthere remains a need for a novel form of hold access ladderwhich is more safe in use than a vertical ladder butwhich is less vulnerable to damageduring unloading ofthecontentsofthe hold. The present invention aimsto meet that need.

The access ladder according to the present invention comprises a first platform for mounting horizontally against a generally vertical bulkhead, a first ladder section pivotally mounted adjacent one of its ends upon said first platform, a second platform pivotally mounted upon the other end of said first ladder section, a second ladder section pivotally mounted upon said second platform, and lifting cable means for raising and lowering said first and second ladder sections and said second platform relative to said first platform.

The access ladder as described is able to pivot aboutthefirstplatform so as to withdraw the ladder upwardsfromthesideofthehold during unloading of the latter, the ladderthen being able to bestowed againstthe underside of the upper deck of the ship. If desired the first platform (which may be otherwise identified as the "upper" platform) may itself be pivoted to the adjacent bulkhead so that the ladder as a whole, when lifted into its stowing position, may be stowed vertically against the bulkhead. However in most situations and for ease of operation, it is sufficientforthe upper platform to be rigidly fixed to the bulkhead, as by bolting or welding.Conveniently the upper platform is mounted adjacentto a conventional short vertical ladder, itself secured to the bulkhead, to provide ready access from the deck ofthe ship to the upper platform.

In use, the upper or first ladder section leads down from the upper platform to the second (or "intermediate") platform, which in turn leads to the second tor "lower") ladder section. By means of this arrangement, ready access can be afforded to the bottom of holds as deep as 20 metres or more below deck level. However, if desired, at leastonefurther intermediate platform and ladder section may be provided at the bottom end of the second ladder section, in order to shorten the ladder runs and/orto afford access to particularly deep holds.

The first and second ladder sections may be pivoted at opposite sides of the intermediate platform but it is preferred that they be pivoted at adjacent points on the same side ofthe platform. For example,thetwo pivots may be aligned or parallel to each other.

Theladdersectionswill normally be provided with side rails, for example hand rails, at least on that side of the ladder sections which lies away from the adjacent bulkhead. The platforms will normally also be provided with rails. By pivotting the rail of the upper ladder section to those of the platforms, it may readily be achieved that the ladder hand rail remains parallel to the ladder section in whatever positions the ladder sections may be, thereby forming a parallel-motion device which maintains the intermediate platform level as the ladder pivots.

The raising and lowering of the ladder is achieved using a system of one or more lifting cables. Thetwo or more ladder sections may be controlled by means of a single continuous cable running from the deckto each ladder section and back in turn or separate cables may be used for each section.

In the ultimate position of use of the ladder, the structure as a whole is preferably stabilised by attaching the intermediate platform to the bulkhead.

This may conveniently be achieved by providing locking pins on the platform designed to self-locate in lugs on the bulkhead. In this position of use, the lower end of the second or lowermost ladder section should preferably rest upon the bottom ofthe hold.

The invention will now be further described with reference to the accompanying drawings, in which:- Figure 1 is a view in front elevation of one embodiment of hold access ladder according to the present invention in its position of use, the ladder in its folded position being shown in broken line; Figure2 is a side elevation of the ladder of Figure 1;and Figure3is a plan view of the ladder of Figures 1 and 2.

The illustrated laddercomprisestwo ladder sections, namely upper and lower sections designated by the reference numerals4and 5 respectively. The treads or steps of the ladder, not shown in Figure 1 ofthe darwings, are fixed relative to the frames of the ladder sections and are so disposed that they are horizontal when the ladder is fully erected.

The upper ladder section 4 is pivotted at 6to a fixed upper platform 7, secured to the bulkhead close beneath the deck 8 of the ship. Access to the platform 7 from the deck 8 is afforded by a short vertical length of ladder 18 mounted on the bulkhead. An intermediate platform 9 is pivotted at 10 to the lower end of ladder section 4 and is also pivotted, on an axis 11 aligned with the pivot line 10, to the upper end ofthe lower ladder section 5.

Theupperand lower ladder sections are provided with hand rails 12 and 13 respectively, each of which is supported from the ladder section upon pivotted parallel stanchions. The hand rail 12 ofthe upper ladder section 4 is pivotally linked at its upper end to afixed handrail 14 mounted on the platform 7 and at its lower end to a hand rail 15 fixedly mounted on the intermediate platform 9. The hand rail 13 is also pivotally linked to the rail 15.

Itwill be clearly seen in Figure 1 ofthe drawings thatthe ladder section 4, its hand rail 12 and the two adjacentuprightstanchions ofthe plafforms 7 and 9 form a parallelogram such that, whatever the orientation of the ladder section, the intermediate plafform 9 will always remain level.

Raising and lowering ofthe ladder assembly is effected buy a single continuous lifting cable 16, operated by a winch 17 mounted on the bulkhead adjacent to the platform 7. Thus, when access to the hold bottom is required, operation ofthewinch 17 allowsthecable 16to unwind and lowerthe upper end lower ladder sections until the intermediate platform 9 approaches its final position. At that point locking pins 19 on the platform 9 self-locate in lugs 20 projecting from the bulkhead and secure the platform, both during lowering ofthe lower ladder section Sand also during subsequent use of the ladderforaccess to the hold.

Subsequent reverse operation of the winch 17 winds up the cable 16 and raisesthe ladder,folding the ladder sections into parallel alignment for stowage underthe deck 8 as shown in broken line in Figure 1.

lnthisposition,thewholeladderstructurelies protected from grabs during an unloading operation but is readily accessible when desired from thefixed platform 7.

Claims (11)

1. An access ladder comprising a first platform for mounting horizontally against a generallyvertical bulkhead, a first ladder section pivotally mounted adjacent one of its ends upon said first platform, a second platform pivotally mounted upon the other end of said first ladder section, a second ladder section pivotally mounted upon said second platform, and lifting cable means for raising and lowering said first and second ladder sections and said second platform relative to said first platform.

2. An access ladderas claimed in claim 1, wherein said first platform is itself pivoted to the adjacent bulkhead.

3. An access ladder as claimed in claim 1, wherein said first platform is rigidly fixed to the adjacent bulkhead.

4. An access ladder as claimed in any of the preceding claims, wherein a vertical ladder is secured to the bulkhead between said first platform and the deck of the ship.

5. An access ladder as claimed in any ofthe preceding claims, having a further platform atthe lower end of said second ladder section and having also a further ladder section linked to said further platform.

6. An access ladderas claimed in anyofthe preceding claims, wherein said first and second ladder sections are pivoted at adjacent points on the same side of said second platform.

7. An access ladder as claimed in any ofthe preceding claims, wherein said first laddersection and said first and second platforms each have a side rail on at least one side thereof and wherein the side rail ofthe first ladder section is pivoted to the side rails ofthefirstand second platforms.

8. An access ladder as claimed in any ofthe preceding claims, wherein said lifting cable means is a single continuous cable.

9. An access ladder as claimed in any ofthe preceding claims, wherein said second platform is adapted for reversible attachment to the adjacent bulkhead in the lowered position of said second platform.

10. An access ladder as claimed in claim 9, wherein said second platform is provided with locking pins designed to self-locate in lugs on said adjacent bulkhead in the lowered position of said second platform.

11. An access laddersubstantially as hereinbefore described with reference to, and as illustrated in, the accom panyi ng d rawi ngs.