GB2137681A

GB2137681A - Folding ladder

Info

Publication number: GB2137681A
Application number: GB08309479A
Authority: GB
Inventors: Frederick Brown
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-03-17
Filing date: 1983-04-07
Publication date: 1984-10-10
Also published as: GB8309479D0; GB2137681B

Abstract

A folding ladder comprises a number of sections (1 to 4), each of which has its side pieces pivoted at their ends to the ends of the side pieces of the next adjacent section. The uppermost section has hooks (6) for engaging a window ledge. Each pivotal joint comprises a link (15) extending between pins (14) on the adjacent side pieces. Each uppermost side piece of a pivoted pair has a locking sleeve (21) which may slide down over the pivotal link when the ladder is extended to lock the joined side members together one aligned with the other. <IMAGE>

Description

SPECIFICATION Folding ladder This invention relates to a folding ladder which may be particularly suitable as a household fire escape, although other uses for such a ladder will be apparent.

A household fire requires immediate action, and the first priority must be always be the evacuated of those within the house. Knotted bed sheets, ropes and rope ladders have all been used, but many people are afraid of using these non-rigid means of descent. Ladders can be raised from the ground, but this requires initiative on the part of people outside the buiiding. Permanent fire escapes can be erected, but their cost is usually prohibitive for the average householder. The present invention has for its objective the provision of a folding ladder which can be used as a reliable and acceptable fire escape for a domestiv property.

According to the invention a folding ladder comprises a number of sections each of which has its side pieces pivoted at their ends to the ends of the side pieces of the next adjacent section, the upper end of the upper section being provided with means for anchoring the top of the ladder, each pivoted joint comprising a pin secured to each side piece and a link pivoted about each of the pins, means for preventing pivoting movement of the side pieces beyond a point where they are aligned one with the other, and a sleeve slidable over adjacent parts of the side pieces to lock them in the aligned position.

When folded, the ladder is compact and may be stored in a suitably accessible place.

To use the ladder the top of the ladder is anchored by the anchoring means which may, for example, be a hook arrangement capable of hooking over a window still so that the upper end of the ladder is firmly secured. The sections of the ladder are then unfolded from the top of the ladder this action being assisted by the effect of gravity. As the side pieces of each section move into alignment with the side pieces of the section immediately thereabove the sleeves drop downwardly to lock the side pieces in their alignment positions, thus, as an automatic operation the ladder is extended and locked in its extended position and provides a substantially rigid escape route from the building.

Preferably each sleeve is normally retained on the side piece which will be uppermost when the ladder is unfolded, and is a sufficiently loose fit on that side piece to allow the sleeve to fall under gravity to a position partially engaging both upper and lower side pieces when these are in the aligned position.

This simple sliding action of the sleeves materially assists the rapid and automatic deployment of the ladder.

In order that the invention may be better understood a specific embodiment of ladder in accordance therewith will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side elevation of the ladder in the folded position; Figure 2 is a side elevation of the extended ladder, to a smaller scale; Figure 3 is a front elevation detail of a joint of the ladder in the open position; Figure 4 is an enlarged side elevation detail of a joint of the ladder in the folded position; Figure 5 is a perspective view of a sleeve; and Figure 6 is a section on the line VI-VI of Fig. 3.

The ladder shown in the drawings comprises four folded sections 1 to 4, although it will be understood that any appropriate number of sections may be used according to the length of the ladder required. The top end of the uppermost section has secured thereto about pivots 5 two hooks 6, one at each side of the ladder, the hooks being designed so that they may readily hook over a window ledge and provide firm anchoring for the ladder from the window ledge. Each section of the ladder comprises two side pieces 7 joined by rungs 8 in the usual way. The lowermost section 4 of the ladder may, if required, have a stay 9 pivotally secured thereto in order to improve the stability of the ladder when in the open position.

Referring to Figs. 3 to 5 each side piece is of hollow rectangular section and has opposed side elements 10, 11 and opposed end elements 12, 13. A pivot pin 14 extends between the side elements 10 and 11 of each side piece and is secured in position by, for example, swaging or welding at its two ends.

A link 1 5 extends between the pivot pins 14, the link having two elongated holes 16, 17, one fitting over each pin. The link is centralised between the side members 10, 11 by spacing washers 18, 1 9 and projects through a cut-out section 20 in the end wall 1 3 of each side piece. Part of the end of each side piece is curved as shown at 21, 22 in Fig. 4 to allow unfolding of the side pieces about the pivot pins 14 without the side pieces fouling one another. This action is further facilitated by the elongated holes 16, 1 7 in the link 1 5.

The end wall 1 2 of the side piece is not cut away and acts as a stop for the link preventing the link from pivoting past a position wherein the side pieces of adjacent sections are substantially in alignment.

Each upper side piece of a pivoted pair carries thereon a sleeve 21 which, as shown in Fig. 5, is substantially of channel section to enclose one side element and the opposed end elements of each side piece, the channel section having inturned flanges 22, 23 which engage the other one of the opposed side elements. The sleeve is thus captive on the side piece and partially encompasses the outer periphery of the side piece. The sleeve is designed to be a loose sliding fit over the side piece, so that when the ladder is extended the link may siide downwardly under the effect of gravity to a position where it bridges the link and partially engages the two side pieces lying above and below the link. The sleeve thus blocks the side pieces in their aligned positions and prevents further pivotal movement at the joint. In this position, the sleeve is held against falling further by engagement of a bar 24 with the uppermost rung of the lower of the two pivoted sections.

The ladder may conveniently be manufactured in light aluminium alloy in sections that may suitably be of about four feet in length.

This choice of material and length gives ready portability to the ladder and also allows it to be stored in a resonably small space beneath a bed or window. It will be understood that details of the ladder may be modified from those shown in the drawing without departing from the invention.

Claims

CLAIMS:

1. A folding ladder comprising a number of sections each of which has its side pieces pivoted at their ends to the ends of the side pieces of the next adjacent section, the upper end of the upper section being provided with means for anchoring the top of the ladder, each pivoted joint comprising a pin secured to each side piece and a link pivoted about each of the pins, means for preventing pivoting movement of the side pieces beyond a point where they are aligned one with the other, and a sleeve slidable over adjacent parts of the side pieces to lock them in the aligned position.

2. A folding ladder according to claim 1 in which each sleeve is normally retained on the side piece which will be uppermost when the ladder is unfolded, and is a sufficiently loose fit on that side piece to allow the sleeve to fall under gravity to a position partially engaging both upper and lower side pieces when these are in the aligned position.

3. A folding ladder according to claim 2 in which the sleeve partially encompasses the outer periphery of the side pieces.

4. A folding ladder according to any one of the preceding claims in which the ends of adjacent side pieces are rounded to facilitate their relative pivotal movement.

5. A folding ladder according to any one of the preceding claims in which the link has elongate holes, through each of which a respective one of the pins passes.

6. A folding ladder substantially as herein described with reference to the accompanying drawings.

6. A folding ladder according to any one of the preceding claims in which each link lines between side elements of the respective side piece, and is located relative to these elements by washers between the link and the side elements.

7. A folding ladder substantially as herein described with reference to the accompanying drawings.

1. A folding ladder comprising a number of sections each of which has its side pieces pivoted at their ends to the ends of the side pieces of the next adjustment section, the upper end of the upper section being provided with means for anchoring the top of the ladder, each pivoted joint comprising a pin secured to each side piece and a link pivoted about each of the pins, means for preventing pivoting movement of the side pieces beyond a point where they are aligned one with the other, and a sleeve, normally retained on the side piece which will be uppermost when the ladder is unfolded and a sufficiently loose sliding fit on that side piece to allow the sleeve to fall under gravity to a position partially engaging both upper and lower side pieces when these are in the aligned position, so as to lock them in that position.

2. A folding ladder according to claim 1 in which the sleeve partially encompasses the outer periphery of the side pieces.

3. A folding ladder according to either of the preceding claims in which the ends of adjacent side pieces are rounded to facilitate their relative pivotal movement.

4. A folding ladder according to any one of the preceding claims in which the link has elongate holes, through eac of which a respective one of the pins passes.

5. A folding ladder according to any one of the preceding claims in which each link lies between side elements of the respective side piece, and is located relative to these elements by washers between the link and the side elements.