GB2190419A

GB2190419A - Step ladders

Info

Publication number: GB2190419A
Application number: GB08612017A
Authority: GB
Inventors: Arthur Albert Gould
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-05-16
Filing date: 1986-05-16
Publication date: 1987-11-18
Also published as: GB8612017D0

Abstract

A step-ladder in which a ladder-support member comprises a first section 3a joined by hinges to the ladder portion of the step-ladder and a second section 36 including a pair of spaced and generally parallel upright members joined by a cross piece 4. The two sections are adapted to slide one relative to the other thereby to vary the length of the support member relative to that of the ladder portion. <IMAGE>

Description

SPECIFICATION Improvements in and relating to step-ladders This invention relates to step-ladders.

Conventional step-ladders are generally oniy safe to use on floors or ground surfaces which are level or moderately inclined. One particular occasion where conventional step-iadders cannot safely be used is in the confines of, for example, stairwells.

Use of a conventional ladder resting against a wall surface can lead to damage to that surface and any attempt to erect a conventional step-ladder with the ladder and support sections resting on stairs at different levels is both foolhardy and dangerous.

Scaffolding can be employed in these circumstances, however, its assembly is difficult and time-consuming in the limited space available.

Step ladders in which each of the four legs in contact with the ground can be independently adjusted are known for use on uneven ground surfaces. Such step ladders have failed to achieve commercial success because of high manufacturing costs caused by over-complicated designs, concern that with four adjustable extension pieces may break or be improperly extended with consequent risk to the safety of the user, and the fact that the step ladder, when assembled, is inherently less stable than a conventional step ladder.

The present invention sets out to provide a step ladder for use particularly in cases where the ladder legs are located on a level surface at a height different from that on which the support legs are located, and which can readily and simply be converted to provide a conventional step ladder for use on a level surface.

According to the present invention there is provided a step-iadder which the ladder-support member comprises a first section joined by hinges to the ladder portion of the step-ladder and a second section including a pair of spaced and generally parallel upright members joined by a cross piece, the two sections being adapted to slide one relative to the other thereby to vary the length of the support member relative to that of the ladder portion.

In a preferred arrangement, the slidable sections telescope one within the other. The sections may include one or more apertures which when aligned can receive locking pins operable to lockthe relatively slidable leg sections in position.

Alternatively, a clamping device or ratchet may be provided for this purpose. One such clamping device may comprise a screw-threaded member which protrudes from the outer section and can be rotated to bear firmly against the inner section.

According to the present invention in another aspect, there is provided a step-ladder including cooperating ladder and ladder-support members which can be inclined one with respect to the other to provide a stable assembly, the support-member comprising an upper tubular section and a lower section including a pair of generally parallel upright members joined by a cross piece and adapted to slide within the upper section, and means operable to lock the two sections together to vary the overall length of the ladder-support member.

The cross-piece preferably extends between the lower ends of the upright members.

The invention will now be described by way of example only with reference to the accompanying drawings in which: Figure lisa side elevational view of a step ladder in accordance with the invention when assembled for use on a flight of stairs; Figure 2 is a side elevational view of the ladder illustrated in Figure.1 in its folded position; and Figures 3 and 4 are respectively front and back views of the ladder illustrated.

The step-ladder illustrated in Figure 1 of the drawings is shown when assembled for use on a staircase.

The step-ladder illustrated includes a runged ladder 1 which is connected by hinges 2 to a laddersupport member 3. The member 3 comprises two generally parallel elongate members joined by a cross-piece 4 to provide a unitary structure. The cross-piece 4 is positioned to provide a safe seating for the support member 3 on the appropriate ground surface. When assembled, the ladder 1 and support member 3 are mutually inclined to provide a stable structure. Pivotable side struts 5 extend between the ladder 1 and support member 3 to give enhanced stability.

The support member includes upper and lower lower sections 3a, 3b adapted to slide one within the other. As illustrated, the lower section 3b is dimensioned such that it can telescope within the upper section 3a. Each leg of the lower section 3b includes a series of holes 8 which can be aligned with holes formed in the uprights of the upper sections 3a. Locking pins 9 are provided to lock the sections 3a, 3b in a required position thereby to enable the overall length of the support member 3 to be varied.

As will be seen from Figure 1 of the drawings, this ability to vary the length of the support member 3 enables the step-ladder to be used in a stairwell whilst retaining the stability required for safety.

When not required for use on uneven or irregular floor surfaces, the lower section 3b can be extended fully so that the step-ladder can be used conventionally on generally level surfaces.

Preferably the relatively slidable sections of the support member 3 are manufactured from a material such as aluminium or steel and may be of box-section or formed from sections (e.g. a "U" section) suitable to enable the required sliding movement to take place. Captive rollers may be provided within the co-operating sections to facilitate ease of sliding.

It is to be understood that the foregoing is merely exemplary of one embodiment of a step-ladder in accordance with the invention and that various modifications can be made to the step-ladder described without departing from the true scope of the invention. Thus, the locking pins 9 may be replaced by, for example, one or more screw threaded lead screws moveable into engagement with the innermost section of the support member 3. Alternatively, some form of ratchet arrangement may be provided. In a further arrangement, one sliding section is formed with an elongate toothed rack which co-operates with a worm gear wheel rotatable by a handle connected via a drive shaft to the worm wheel to move the lower section 3b relative to the upper section 3a.

Claims

1. A step-ladder in which a ladder-support member comprises a first section joined by hinges to a ladder portion of the step-ladder and a second section including a pair of spaced and generally parallel upright members joined by a cross piece, the two sections being adapted to slide one relative to the other thereby to vary the length of the support member relative to that of the ladder portion.

2. A step ladder as claimed in claim 1 wherein the slidable sections telescope one within the other.

3. A step ladder as claimed in claim 1 or claim 2 wherein the sections include one or more apertures which when aligned can receive locking pins operable to lock the relatively slidable leg sections in position.

4. A step ladder as claimed in claim 1 or claim 2 wherein a ratchet device is provided to lock the relatively slidable leg sections in position.

5. A step ladder as claimed in claim 1 or claim 2 wherein the slidable sections are locked in position by means of a clamping device comprising a screwthreaded member which protrudes from the outer section and can be rotated to bear firmly against the inner section.

6. A step-ladder which includes co-operating ladder and ladder-support members which can be inclined one with respect to the other to provide a stable assembly, the support-member comprising an upper tubular section and a lower section including a pair of generally parallel upright members joined by a cross piece and adapted to slide within the upper section, and means operable to lock the two sections together to vary the overall length of the ladder-support member.

7. A step ladder as claimed in claim 6 wherein the cross-piece extends between the lower ends of the upright members.

8. A step ladder as herein described with reference to Figures 1 to 4 of the accompanying drawings.