GB2261905A

GB2261905A - A ladder and a kit for assembly into a ladder

Info

Publication number: GB2261905A
Application number: GB9224364A
Authority: GB
Inventors: George Henry Peter Bowman; Martin Leslie Hill
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-11-26
Filing date: 1992-11-20
Publication date: 1993-06-02
Anticipated expiration: 2012-11-20
Also published as: GB2261905B; GB9125120D0; GB9224364D0

Abstract

A ladder for use on sailing boats to climb the mast comprising a number of rungs (40) and longitudinal members (46, 48) interconnecting the rungs includes retraction means for retracting the or each longitudinal member to hold one rung which each longitudinal member is connected to against an adjacent rung in the ladder when the former rung is not in use. A kit for assembly into a rope ladder is disclosed (figure 1), comprising two longitudinal members (10) and a plurality of rungs (20), each rung being arranged to be individually mountable between the longitudinal members and individually removable therefrom in the assembled ladder. <IMAGE>

Description

A LADDER AND A KIT FOR ASSEi INTO A LADDER The invention relates to a ladder and to a kit for assembly into a ladder, and relates particularly but not exclusively to a ladder and to a kit for assembly into a ladder which is suitable for use on sailing boats.

When sailors encounter problems with a boat's mast, it is often necessary for them to climb the mast to facilitate repairs.

Bosun's chairs are known and are used in most situations to reach the upper part of a mast. Using a pulley system to lift a person up the mast, the Bosun's chair normally requires at least two people to operate. This present difficulties for single-handed sailors who wish to reach the upper part of a mast.

A conventional ladder is a large item to store and its size and shape may make storage difficult in particular where space is limited, for example on a boat.

NL 8901410 discloses a collapsible ladder comprising a plurality of hollow rungs interconnected by a pair of ropes which pass through an aperture adjacent each end of the rung.

The lengths of rope which interconnect the rungs are manually retracted into the bore of the rungs using a separate tool when the ladder is placed in the retracted condition.

Use of the ladder disclosed in NL 8901410 is limited by the need for a separate tool when contracting the ladder and by the relatively long time which it takes to contract the ladder.

According to one aspect of the invention there is provided a ladder comprising a number of rungs and longitudinal members interconnecting the rungs including retraction means for retracting the or each longitudinal member to hold one rung which each longitudinal member is connected to against the adjacent rung in the ladder when the former rung is not in use.

Thus this aspect of the invention provides a ladder which overcomes the disadvantages of the ladder of NL 8901410.

Preferably, retraction means are provided for retracting both longitudinal members whereby the entire ladder collapses when not in use to a compact size.

The longitudinal members may be flexible. For example the longitudinal members may be in the form of tapes or chain.

Tapes made of a strong material such as a nylon are preferred because of its relatively light weight.

The retraction means may be arranged to retract each longitudinal member into a rung which it interconnects with another rung.

The retraction means may comprise a resilient member.

Preferably the retraction means comprises a spring which may be a tension or compression spring. Two retraction means may be associated with each rung whereby the longitudinal members on each side of the ladder can be retracted into each rung.

Each intermediate rungs, that is to say a rung intermediate the rungs at either end of the ladder, may therefore be provided with retraction means for retracting four longitudinal members i.e the longitudinal members on either end of the rung connecting that rung to the rungs above and below that rung in the ladder.

The retraction means may be arranged to provide extension of the longitudinal members. Preferably, the retraction means is arranged to retract the ladder rungs when there is no pressure on a rung e.g from a user but to allow extension when pressure is applied. Preferably means are provided for restricting the extension of the longitudinal member. The said means may be in the form of a stop. Where the retraction means is in the form of a spring said means may comprise a member which contacts a portion of a rung to limit extension of the longitudinal member.

Interlock means may be provided permitting interlocking of a selection of, or adjacent rungs when the entire ladder is in a contracted condition due to retraction of the longitudinal members. Preferably the interlock means are in the form of cooperating structures provided by adjacent rungs. In a preferred embodiment projections in the tread on one rung in the ladder engage correspondingly-shaped recesses formed in the underside of a rung immediately above the former rung when the longitudinal member(s) interconnecting the rungs is/are retracted whereby relative transverse movement of the rungs is prevented.

According to another aspect of the invention there is provided a kit which can be compactly stored as separate longitudinal members and rungs and which can be assembled into a ladder when required.

Thus, according to this aspect of the invention, there is provided a kit for assembly into a ladder, the kit comprising two longitudinal members and a plurality of rungs, each rung being arranged to be individually mountable between the longitudinal members and individually removable therefrom in the assembled ladder.

In this way assembly and disassembly of the ladder is facilitated and individual rungs can be removed easily, for example, for storage, repair or replacement.

The longitudinal members may be flexible and preferably are so flexible that they can be coiled. The ladder in this form can then be stored in a small volume and without the need to cater for the overall length of the longitudinal members. The longitudinal members may be made from rope which may be steel rope and, for example, may be made from wire or cable.

Preferably, each rung. is arranged to be mounted to each longitudinal member on a mounting member. The rungs are thus mounted on mounting members at both ends. Each rung is preferably arranged to be mounted on a mounting member without tools. The ladder can thus be readily assembled. Each rung may snap interengage onto a mounting member providing a tight mounting for the rung. Each rung may include a downwardly facing recess in which a mounting member is received to mount the rung. Thus when a load is applied, i.e a foot on the rung, the rung is secure. Each rung may include a channel provided between the downwardly facing recess and the periphery of the rung and preferably the channel is not straight. This will further secure the rung from becoming accidentally detached from the longitudinal member. The channel may include an upright portion and a transverse portion.The channel may comprise a transverse portion leading from the periphery of the rung to an upright portion which leads upwardly to the downwardly facing recess.

Each rung may include a through recess to receive the longitudinal member. The through recess may face outwardly from the end of the rung. This reduces the probability of the longitudinal members moving out of the rung groove.

Each mounting member may extend on both sides of the longitudinal member to which it is attached and each rung may be arranged to engage the mounting member on both sides of the longitudinal member. This produces a balanced distribution of the load. Each mounting member may be a peg. In the embodiment where the longitudinal member is a rope, each peg may be attached to the rope by being trapped between two strands of the rope. This greatly simplifies the production of the kit. Each mounting member may be a bead. The bead is preferably rounded at least on its upper surface and may be peripheral to that bead is distributed more evenly on a greater surface area thus reducing stress, in the mounting member.

Preferably the longitudinal members are arranged to join at an end. The kit may include a ring and the longitudinal members may be arranged to be joined to the ring at an end.

That provides a convenient way to hang the ladder or to lift the head of the ladder to a desired point, e.g the top of a mast on a boat. The longitudinal members may be arranged to be joined at both ends.

Each rung may be formed from an extrusion, for example from aluminium. Alternatively each rung may be formed from sheet material. Each rung may comprise an outer shell having strengthening material there within. The outer shell may be made from metal. The strengthening material may be a plastics material.

According to further aspect of the invention there is provided a ladder assembled from a kit as described above.

The invention will now be described with reference to the accompanying drawings Figs 1 to 16 wherein: Fig. 1 is an elevation of a portion of a ladder in accordance with one embodiment of the invention showing one rung mounted across the longitudinal members and mounting means without a rung mounted thereon; Fig. 2 is a detail perspective view of the embodiment of Fig.

1, showing the mounting arrangement at one end of a rung; Fig. 3 is a detail perspective view of the end of a rung of the embodiment of Fig 2; Fig. 4. is a detail perspective view of a ladder in accordance with another embodiment of the invention, showing the mounting arrangement of one end of a rung the rung being shown in crosssection for clarity; Fig. 5 is a detail perspective view of the end of a rung of the embodiment of Fig. 4; Fig. 6 is a detail perspective view of a ladder in accordance with a further embodiment of the invention showing the mounting arrangement of one end of a rung; Fig. 7 is a detail perspective view of the end of a rung of the embodiment of Fig. 6; Fig. 8 is an elevation of an embodiment of the assembled ladder; Fig. 9 is a perspective view of the kit of the embodiment of Figs. 4 and 5;; Fig 10 is a perspective view of an alternative rung for use in the ladder of the invention shown in Figs 1, 2 and 3; Fig. 11 is a lateral cross-section through a rung of a ladder in accordance with the said further aspect of the invention; Fig. 12 is a longitudinal cross-section through the rung of Fig. 11; Fig. 13 is a detail side view of a portion of the rung of Figs.

11 and 12; Fig. 14 is a detail elevation of the portion shown in Fig. 13; Fig. 15 is a perspective cut away view of a portion of the rung shown in Figs. 11 and 12; and Fig. 16 is a cross-section through portions of the rung of Figs. 11 and 12.

The kit of the embodiment shown in Fig. 1 comprises two steel ropes 10 (the aforesaid "longitudinal members"), aluminium rungs 12 and mounting members 14.

The ropes 10 have mounting members 14 regularly spaced along their length. The ropes are joined at each end by a ring 8 (see Figs. 8 and 9).

The mounting members 14 include an aperture 16, formed as part of the rope 10 on which the mounting member 14 is located, and a mounting peg 18 disposed transverse to the axis of the rope 10 and running through the aperture 16. The ropes 10 are whipped immediately above and below the mounting members 14 to prevent the rope from unravelling.

The rung 12 has a body 20 and two ends 22. The ends 22 of the rung 12 (see Fig. 2 and 3) have a through recess 24 which is disposed between two L-shaped locking groove 26. The through recess 24 faces outwardly from the end 22 of the rung 12 and receives the longitudinal member 10.

To assemble a rung 12 onto its mounting members 14, the mounting peg 18 is slid along the transverse portions of the L-shaped locking grooves 26 such that the rope 10 is disposed in the through recess 24. The rung 12 is then locked into place by the mounting peg 18 being received in the upright portions of the L-shaped locking groove 26. When load is applied to the upper surface of the rung 12, the load is distributed through the mounting peg 18 and into the ropes 10.

To remove a rung 12 from its mounting members 14, the rung is pushed upwardly and the mounting pegs 18 are slid from the L shaped locking grooves 26.

In another embodiment of the invention (see Figs. 3, 7) the mounting member 14 comprises a bead 40 attached to the ropes 10. The rung 12 has at its end 22 a through recess 24 and a receiving chamber 42 which receives the bead 40.

In a further embodiment of the invention (see Figs. 6, 7) the mounting member 14 is substantially as described in the first embodiment but the end 22 of the rung 12 has a keyhole shaped locking groove 50, into which groove 50 the mounting peg 18 snap interengages.

The rung 28 shown in Fig. 10 is for use in holding the other rungs of the ladder away from the mast. The rung 28 is of unitary construction and is shaped to define a concave surface 30. The rung 28 is arranged to fit onto the ropes of a ladder of the type shown in Fig. 1 by means of through recesses 24 and locking grooves 26, as described above in relation to the rungs illustrated in Figs. 2 and 3.

In use, the rung 28 is fitted as the top rung of the ladder and the ladder is connected to the top of the mast as described above. The surface 30 butts against the surface of the mast keeping the upper portion of the ladder away from the mast.

The lower portion of the mast can then be tensioned to keep the whole ladder spaced apart from the mast.

The intermediate rung 40 of the ladder shown in Figs. 11, 12 and 15 incorporates the retraction means referred to above and is formed from a hollow aluminium extrusion. The rung 40 is interconnected with rungs immediately above and below it in the ladder by strong, flexible tapes 42, 44, 46, and 48, made for example from nylon which constitute the above mentioned longitudinal members. Tapes 42, 44 and 46, 48 form respective pairs. The pairs of tapes are connected to tension springs 50, 52 respectively which are fixed to an upright member 54 intermediate the ends of the rung.

In retracted condition (i.e when the ladder is not in use), as shown in Fig. 11, the springs 50, 52 are in maximum compression and hold the rungs immediately above and below rung 40 against rung 40. In practice, tapes 42-48 will lie flatter against the ends of the rung 40 than is shown in Fig. 11.

In the extended state (i.e when pressure is applied to the rung 40 or the rung immediately below rung 40 in the ladder from above) the tapes 42-48 will be pulled out of the ends of the rung 40 as shown in Fig. 12. Extension of springs 50 and 52 is limited by pegs 56 and 58 abutting the ends caps 57,59 of the rung 50, whereby the elastic limit of each spring is not exceeded. In the event of a spring failing, pegs 56 and 58 provide a fail safe mechanism allowing the ladder to be used but without the retraction facility.

Pegs 54 and 56 slide on runners e.g 60,62 shown clearly in Fig.

15.

It will be appreciated that when pressure is applied to the top rung of the ladder, when the ladder is in the contracted state, that rung will drop down as its springs extend and the tapes which connect that rung to the rung which is immediately adjacent below will extend separating the two rungs. Thus a user will be able to place his or her foot on the lower rung and the resulting pressure on that rung will cause the separation of the rung immediately below it. In effect therefore the ladder is self extending.

An extruded aluminium tread 64, shown in Fig. 16, provided with longitudinal recesses e.g 66 is fixed to the top of the rung 40. A base plate 68, also shown in Fig. 16, is fixed to the base of rung 40 and is provided with complimentary projections, e.g 70, which fit into the longitudinal recesses in the tread of the rung immediately below the rung 40 when the ladder is in a contracted condition.

Although particularly useful for use in reaching the upper part of a boat's mast the ladder of the invention can also be used for example as a boarding ladder or in a "man over board" situation or as a fire escape..

Claims

1. A ladder comprising a number of rungs and longitudinal members interconnecting the rungs including retraction means for retracting the or each longitudinal member to hold one rung which each longitudinal member is connected to against an adjacent rung in the ladder when the former rung is not in use.

2. A ladder according to claim 1 in which retraction means are provided for retracting both longitudinal members whereby the entire ladder collapses when not in use to a compact size.

3. A ladder according to claims B or 2 in which the longitudinal members are flexible.

4. A ladder according to claim 3 in which the longitudinal members are in the form of tapes or chain.

5. A ladder according to claim 4 in which the tapes are made of a nylon.

6. A ladder according to any preceding claim in which the retraction means are arranged to retract each longitudinal member into a rung which it interconnects with another rung.

7. A ladder according to any preceding claim in which the retraction means comprises a resilient member.

8. A ladder according to claim 7 in which the retraction means comprises a spring which may be a tension or compression spring.

9. A ladder according to any preceding claim in which the two retractions means are associated with each rung whereby the longitudinal members on each side of the ladder can be retracted into each rung.

10. A ladder according to any preceding claim in which the retraction means are arranged to provide extension of the longitudinal members.

11. A ladder according to any preceding claim in which the retraction means is arranged to retract the ladder rungs when there is no pressure on a rung but to allow extension when pressure is applied.

12. A ladder according to claims 10 or 11 in which means are provided for restricting the extension of the longitudinal member.

13. A ladder according to claim 12 in which the said means is in the form of a stop.

14. A ladder according to claims 12 or 13 and where the retraction means is in the form of a spring in which said means comprises a member which contacts a portion of a rung to limit extension of the longitudinal member.

15. A ladder according to any preceding claim in which interlock means are provided permitting interlocking of a selection of, or adjacent rungs when the entire ladder is in a contracted condition due to retraction of the longitudinal members.

16. A ladder according to claim 15 in which the interlock means are in the form of cooperating structures provided by adjacent rungs.

17. A ladder according to claim 16 in which projections in the tread on one rung in the ladder engage correspondinglyshaped recesses formed in the underside of a rung immediately above the former rung when the longitudinal member(s) interconnecting the rungs is/are retracted whereby relative transverse movement of the rungs is prevented.

18. A kit for assembly into a ladder, the kit comprising two longitudinal members and a plurality of rungs, each rung being arranged to be individually mountable between the longitudinal members and individually removable therefrom in the assembled ladder.

19. A kit according to claim 18 in which the longitudinal members are flexible and preferably are so flexible that they can be coiled.

20. A kit according to claim 18 or 19 in which the longitudinal members are made from rope which may be steel rope or nylon and, for example, may be made from wire or cable.

21. A kit according to any one of claims 18 to 20 in which each rung is arranged to be mounted to each longitudinal member on a mounting member.

22. A kit according to claim 21 in which each rung is arranged to be mounted on a mounting member without tools.

23. A kit according to claim 22 in which each rung snap interengages onto a mounting member.

24. A kit according to claims 22 or 23 in which each rung includes a downwardly facing recess in which a mounting member is received to mount the rung.

25. A kit according to claims 21, 22, 23 or 24 in which each rung includes a channel provided between the downwardly facing recess and the periphery of the rung and preferably the channel is not straight.

26. A kit according to claim 25 in which the channel includes an upright portion and a transverse portion.

27. A kit according to claim 26 in which the channel comprises a transverse portion leading from the periphery of the rung to an upright portion which leads upwardly to the downwardly facing recess.

28. A kit according to any one of claims 18 to 27 in which each rung includes a through recess to receive the longitudinal member.

29. A kit according to claim 28 in which the through recess faces outwardly from the end of the rung.

30. A kit according to any one of claims 21 to 29 in which each mounting member extends on both sides of the longitudinal member to which it is attached and each rung is arranged to engage the mounting member on both sides of the longitudinal member.

31. A kit according to any one of claims 21 to 30 in which each mounting member is a peg.

32. A kit according to any one of claims 21 to 30 in which each mounting member is a bead.

33. A kit according to any one of claims 18 to 32 in which the longitudinal members are arranged to join at an end.

34. A kit according to any one of claims 18 to 33 in which each rung is formed from an extrusion.

35. A kit according to any one of claims 17 to 32 in which each rung is formed from sheet material.

36. A kit according to any one of claims 18 to 35 in which each rung comprises an outer shell having strengthening material there within.

37. A ladder assembled from a kit as described above.

38. A ladder or a kit for a ladder substantially as described herein and as illustrated in the accompanying drawings.