GB2160250A - Stepladder - Google Patents

Abstract

A folding ladder (10) having its legs (18) pivotally connected such as to permit their mutually independent angular movement towards the closed condition of the ladder. A single length of cord (28) extends from one leg (18) to a cord- direction-changing device fast with the main unit (15) and from said device to the other leg (18), for limiting the angular movement of the legs (18) from the closed to the open condition. The device comprises an elongate plate (24) having one long edge attached to a generally cylindrical member (25) such as to extend in a radial plane of said member (25), two longitudinally spaced apertures (26) being provided adjacent the arris between plate (24) and member (25), the cord (28) extending through both said apertures (26) and between them following a substantially helical path over the surface of the said member (25). <IMAGE>

Description

SPECIFICATION Ladders This invention relates to ladders and in particular to so-called folding ladders (hereafter referred to as of the kind defined) comprising steps or rungs extending between a pair of upstanding side supports to form a main unit that is pivotally connected towards the top to a pair of legs. With the ladder in use in its open condition the legs are splayed apart from the side supports but angularly approach the side supports as the ladder is folded up to its closed position. It is intended that certain forms of so-called trestles are to be deemed folding ladders the kind defined.

Known folding ladders of the kind defined have the pair of legs constructed as a secondary unit which is hinged towards the top of the main unit such that in use the angular spacing between one side support and the leg associated with said one side support is always exactly the same as the angular spacing between the other side support and the leg associated with said other side support.

Conventionally, two pieces of cord (or other flexible element) of equal length are attached by their ends to the two units so as to limit the extent of said angular spacing. Such known folding ladders are only suitable for safe use on even ground and cannot be safely used, say, where one of the legs is to rest on ground at a level different from that upon which the other leg is to rest.

With a view to overcoming this disadvantage, the present invention (in one aspect) provides a folding ladder of the kind defined wherein said legs are pivotally connected such as to permit their angular movement towards said closed condition independently of one another.

Preferably the folding ladder is provided with means for limiting the angular movement of the legs from the closed condition to the open condition.

Said limiting means may comprise a length of cord extending between each side support and the leg adjacent that side.

Preferably said limiting means comprises a single length of cord extending from one leg to a cord-direction-changing device fast with said main unit and from said device to the other leg. With such an arrangement angular movement of one leg in one direction is accompanied by an angular movement of the other leg in an opposite direction and of equal magnitude.

Advantageously said single length of cord is in the form of a closed loop extending through apertures in said legs for resisting any tendency for the legs to move apart laterally.

The cord-direction-changing device may comprise a simple apertured member attached to the main unit, the cord extending slidably through the member's aperture. Preferably the cord-direction-changing device comprises an elongate plate having one long edge attached to a generally cylindrical member such that the plate extends in a radial plane of said member, and having two longitudinally spaced apertures provided therein adjacent the arris between plate and member, the cord extending through both said apertures and between them following a substantially helical path over the surface of said generally cylindrical member.

By way of non-limiting example, one embodiment of this invention will now be described with reference to the accompanying drawing which is a perspective view of a folding step ladder according to this invention.

The illustrated folding step ladder 10 comprises a plurality of step-treads 1 2 extending between and fixed to a pair of upstanding side supports 14 so as to form a main unit 1 5.

This main unit 1 5 is provided at the top with a back panel 1 6 to which two legs 1 8 are individually hinged by two separate hinges 20. The two legs 1 8 are thus pivotally connected to the main unit 1 5 towards the top of unit 1 5 in a manner permitting angular movement of the legs from the ladder-open towards the ladder-closed condition and independently of one another.

The ladder 10 is provided with a device 22 which comprises a generally rectangular plate 24 and a generally cylindrical member 25 extending along one longer edge of plate 24 such that the plate extends in a radial plane of member 25. Two longitudinally spaced holes 26 are provided in plate 24 adjacent its arris with member 25. The device 22 is attached to the underside of one of the step-treads 12, e.g. the lowermost step-tread, by means of plate 24, the two holes 26 being beyond the step-tread and thus left uncovered by it. A single length of cord 28 has one end attached to one leg 1 8 and extends therefrom sequentially under member 25, upwardly through one hole 26, helically around member 25, upwardly through the other hole 26, over member 25 and then to the other leg 1 8 to which its other end is attached.The device 22 thus provides a cord-direction-changing device whereby an angular movement of one leg 1 8 in a direction to open the ladder will (when the cord 28 is taut) result in a corresponding angular movement of the other leg 1 8 in the opposite, ladder-closing direction. The cord 28 provides means for limiting the angular movement of the legs from the ladder-closed to the ladder-open condition. Nevertheless, due to the flexibility of the cord 28, both legs 1 8 can be simultaneously brought to the folded-up, ladder-closed position in which they engage the rear of main unit 1 5 along its height dimension.

It will be appreciated that due to the ability of the two legs 1 8 to adopt, independently of one another, different angles of inclination to the main unit 1 5 whilst retaining cord 28 taut between them, the ladder 10 can be positioned with the bottom 30 of main unit 1 5 at one level, the foot 32 of one leg 18 at a different level and the foot 33 of the other leg 1 8 at (a) the same level as bottom 30 of unit 15 or (b) a third level different to both the level of bottom 30 and the level of foot 32 or (c) the same level as the level of foot 32 so as to function as a conventional ladder of the prior art. It will be noted that the drawing illustrates the position of alternative (b).It will be appreciated that when the legs 1 8 are splayed apart to tauten cord 28, the latter's helically wound portion binds itself about cylindrical member 28 and thus provides a frictional resistance to further independent movement of the legs when the ladder is under load, e.g. by a person standing on it.

In a modification of the above-described and illustrated embodiment, the cord 28 is not fastened by its ends to the legs 1 8 but instead passes through holes in the legs 18 and extends between the legs 18, the ends of cord 28 being connected to one another to form a continuous loop. The extension of the cord 28 between legs 1 8 serves (when the cord is held against slipping by device 22) to interconnect the legs and restrain them from mutual sideways, separation, i.e. it resists any tendency for the legs to move apart laterally.

Claims (8)

1. A folding ladder of the kind defined, characterised in that the said legs are pivotally connected such as to permit their mutually independent angular movement towards the closed condition of the ladder.

2. A folding ladder according to Claim 1, characterised by means for limiting the angular movement of the legs from the closed condition to the open condition.

3. A folding ladder according to Claim 2, wherein said limiting means comprise a length of cord extending between each side support and the leg adjacent that side.

4. A folding ladder according to Claim 2, characterised in that said limiting means comprises a single length of cord extending from one leg to a cord-direction-changing device fast with said main unit and from said device to the other leg.

5. A folding ladder according to Claim 4 wherein said single length of cord is in the form of a closed loop extending through apertures in said legs and such as in use to resist any tendency for the legs to move apart laterally.

6. A folding ladder according to Claim 4 or Claim 5, characterised in that cord-direction-changing device comprises an apertured member attached to said main unit, the cord extending slidably through the member's aperture.

7. A folding ladder according to Claim 4 or Claim 5, characterised in that said corddirection-changing device comprise an elongate plate having one long edge attached to a generally cylindrical member such that the plate extends in a radial plane of said member, and having two longitudinally spaced apertures provided therein adjacent the arris between plate and member, the cord extending through both said apertures and between them following a substantially helical path over the surface of said generally cylindrical member.

8. A folding ladder substantially as herein described with reference to and/or as illustrated in the accompanying drawing.