GB2081357A

GB2081357A - Multipurpose ladder

Info

Publication number: GB2081357A
Application number: GB8119055A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-08-06
Filing date: 1981-06-19
Publication date: 1982-02-17
Also published as: DE3029683A1; GB2081357B; DE3029683C2

Abstract

The ladder comprises a ladder unit having two stiles (1b) interconnected by rungs (1a) connected by a hinge with a second ladder unit having two stiles (2b) interconnected by rungs (2a), or with a prop. A hinge is arranged on each stile (2b) of the second ladder unit (2) or the prop, which has locking means (3, 4, 5) by which the stiles (1b) of the first ladder unit (1), which pass through it, are locked when the ladder is spread open, and longitudinally displaceable relative to the stiles (2b) of the second ladder unit or prop when the ladder is folded. The ladder may be used as a step-ladder or as a straight ladder. <IMAGE>

Description

SPECIFICATION Multipurpose ladder The invention relates to a multipurpose ladder which may be used e.g. as a step-ladder or as a straight ladder. A step-ladder is in general composed of two stiles interconnected by rungs, which are by an upper hinge connected to a prop of the ladder, which may be formed e.g. by a frame or by a second ladder unit.

Embodiments of such multipurpose ladders, particularly step-ladders, are known, which enable the prop to be adjusted, the adjustment being possible only in recesses or suspension elements provided for that purpose. This means that the adjustment is possible only to a distance provided for. In addition the user must always look for the provided recess or suspension element which is difficult with long ladders because these devices are always situated at the top end of the ladder.

The aim of the present invention is to devise a multipurpose ladder of the initially described kind, the parts of which are displaceable relative to each other and at the same time adjustment due to the displacement may be steplessly locked.

This aim is achieved by the provision of a multipurpose ladder comprising a ladder unit which unit is composed of two stiles interconnected by rungs and is by a hinge connected to a second ladder unit composed of two stiles interconnected by rungs or to a prop, the ladder being characterised in that the hinge arranged on each stile of the ladder unit or the prop has a locking device by which the stiles of the ladder unit, which pass through it, are locked in position when the ladder is spread open, while being longitudinally displaceable relative to the stiles when the ladder is folded.

A multipurpose ladder according to the invention has the great advantage that it may be positioned also on a sloping ground or on a staircase without attachments to the ladder being needed. The adjustment, i.e. the adaption of the ladder to the existing ground surface may be stepless and the adjustment may be locked.

The invention will now be described in more detail, by way of a preferred embodiment, with reference to the drawings, in which: Figure 1 shows in principle the upper part of a multipurpose ladder according to the invention in the form of a step-ladder, Figure la is a front elevation of the ladder according to Figure 1, Figure 2 shows in principle the upper part of a folded ladder according to Figure 1, illustrating the adjustability due to displacement, Figure 3 is an exploded view showing details of the locking means, Figure 4 shows an arrangement of a multipurpose ladder according to the invention as a step-ladder, Figure shows another arrangement of a multipurpose ladder according to the invention as a step-ladder, Figure 6 shows the use of a multipurpose ladder as a straight ladder, and Figure 7shows an arrangement of a multipurpose ladder according to Figure 5 with an extension unit.

As is apparent from Figure 1, la and 2, the multipurpose ladder according to the invention comprises a ladder unit, which has two stiles 1 b interconnected by rungs 1 a, and a ladder unit 2, which has two stiles 2b interconnected by rungs 2a.

A prop without rungs may be substituted for the ladder unit 2.

Clamping means is provided in the upper part of the ladder unit 2 on the inner sides of each of the two stiles 2b, the clamping means, as is apparent from Figure 3 in detail, being formed by a bolt 3, by an L-shaped clamping element 4, by a guide bracket 5 on which is situated a slide element 6 of plastics, and by a plate 7 which is attached to the inner side of the stile 2b, e.g. by welding. The eccentric bolt 3 has for locking of the clamping means a cylindrical projection 8 having a flat portion 9 and a thread 10. Onto the bolt are sequentially positioned the clamping element 4 with a larger hole 11, the guide bracket 5 with a bore 12, and the plate 7 with an elongate hole 13 in such a way that the engagement of the flat portion 9 with the eccentric bolt 3 causes locking of the bolt on the plate 7 and consequently on the stile 2b.During said positioning the thread 10 passes through a hole 14 in the stile 2b where it can be firmly fixed by means of a nut 15 and a washer 16.

As mentioned, the same clamping means is attached at the same height on the inner side of the stiles 2b.

The bolt 3 is provided with a flat portion 17 and bears onto the movable clamping element 4, which may be made e.g. of brass or another similar material.

For the functioning of the multipurpose ladder according to the invention the ladder unit 1 is so inserted by the stiles 1 b into the space between the respective clamping element 5 and the upper flat portion of the guide bracket 5 that their ladder unit 1 may be brought into any selected position relative to the ladder unit 2. If, as shown in Figure 1, the ladder is spread apart, as indicated by the double arrow 18, the eccentric bolts 3 connected to the ladder unit 2 are firmly pressed by their outer surface against the slightly movable clamping element 4 which in turn presses the stiles 1 b firmly against the upper flat portion of the guide bracket 5, and clamp it thus firmly into direction indicated by the oppositely pointing arrows 19.

A displacement or slipping of the ladder unit 1 relative to the ladder unit 2 is therefore no longer possible. When folded, as shown in Figure 2, the clamping element4 lies in the flat portion 17 of the bolt 3 whereby the clamping element falls off, the stiles 1 b because the force acting in the direction of the two arrows 20 on to the stiles 1 b ceases to act.

The ladder unit 1 can thus be displaced at will relative to the ladder unit 2 in the direction indicated by the double arrow 21. When the two ladder units are spread apart according to Figure 1, they may again be firmly locked in any selected position relative to each other.

Such uses are apparent from Figures 4 to 7.

A multipurpose ladder according to the invention is shown in Figure 4 as a conventional step-ladder in which the units can no longer be displaced relative to each other due to their being firmly locked together as shown in Figure 1. Naturally the ladder may be additionally prevented from further spreading apart by a transverse safety rod 22.

Figure 5 shows a multipurpose ladder according to the invention also as a step-iadder but the ladder unit 1 is displaced relative to the ladder unit 2 to such an extent that in that state the ladder may be positioned e.g. with the ladder unit 2 standing on the floor and the ladder unit 1 standing on a step 23.

Because the ladder is non-slidably locked by the above described clamping of the two ladder units, it can be safely used.

Figure 6 shows the use of the multipurpose ladder according to the invention as a straight ladder. In this case the ladder unit 1 may be displaced at will in the direction of the double arrow 24 while the locking in position is enabled only by hooks which engage at the lower part of the ladder unit with corresponding rungs in the ladder unit 2.

Figure 7 shows a further use of a multiple ladder unit according to the invention corresponding to Figure 5. Also there the ladder unit 1 stands on a step 23 while the ladder unit 2 stands on the floor, the ladder being positioned in the same way as if the ladder unit were standing on an even floor. In addition to the embodiment which is there shown there is also provided a ladder unit 25 which may be displaced to any desired height relative to the ladder unit 1 and locked in known manner.

To be able to pass through the locking means 3, 4, 5, the stiles 1 b must be less spaced from each other than the stiles 2b.

Claims

1. A multipurpose ladder comprising a first and a second unit, each having two spaced apart stiles, in at least one of the units the stiles being interconnected by rungs, the stiles of the second unit carrying each a hinge assembly receiving one of the stiles of the first unit and including clamping means whereby the stiles of the first unit are locked in position when the ladder is spread open, but are longitudinally displaceable relative to the stiles of the second unit when the ladder is folded.

2. A ladder according to Claim 1, wherein the clamping means of each hinge assembly has a cam member, which is firmly fixed to the associated stile of the second unit, and a clamping element and a guide bracket between which passes the associated stile of the first unit, said clamping means being so designed that in the spread apart position of the ladder the associated stile of the first unit is firmly clamped by the clamping element which is pressed thereon by the outer surface of the cam member, but in the folded position of the ladder is free to be longitudinally displaced.

3. A ladder according to Claim 1, wherein the cam member is a substantially cylindrical bolt which is eccentric and/or has a flat portion.

4. A ladder according to Claim 3, wherein the bolt has a substantially cylindrical projection having a flat portion which extends into an elongate hole in a plate which is firmly connected to the associated stile of the second unit.

5. A ladder according to Claim 1 wherein the clamping means has an eccentric bolt which has a flat portion and is firmly screwed on each inner side of the stiles and has a cylindrical projection of smaller diameter on which are situated a substantially L-shaped clamping element with a larger hole and a substantially L-shaped guide bracket with a hole corresponding to the diameter, said clamping element and guide bracket being so situated on the bolt that the stiles passing between the clamping element and the guide bracket are in the spread apart position firmly clamped by the outer surface of the eccentric bolt, or in the folded position are released by the flat portion to be longitudinally displaced.

6. A ladder according to Claim 5 wherein the eccentric bolt has on the front part of the cylindrical projection a flat portion which extends into an elongate hole in a plate, which plate is connected to the stiles by welding, for firm locking of the bolt on the stiles.

7. A multipurpose ladder constructed, arranged and adapted to operate substantially as herein described with reference to, and as shown in, the accompanying drawings.