GB2479202A

GB2479202A - Collapsible scaffolding tower

Info

Publication number: GB2479202A
Application number: GB1005581A
Authority: GB
Inventors: Richard Weston
Original assignee: JAMES LAWRENCE WESTON
Current assignee: JAMES LAWRENCE WESTON
Priority date: 2010-04-01
Filing date: 2010-04-01
Publication date: 2011-10-05
Also published as: GB201005581D0

Abstract

A scaffolding tower is disclosed which comprises two telescopically collapsible ladder structures 12, 14 defining the sides of the tower 10, and a folding gate structure 16 for maintaining the sides of the tower apart. The gate structure comprises two leaves 16a and 16b hinged to one another and to the stiles of the lowermost sections of the ladder structures. The leaves are folded to lie in planes parallel to the two ladder structures when the tower is collapsed. In the invention, the gate structure 16 includes offset hinges 16c arranged in such a manner as to leave a space between the two sides of the tower when in the collapsed state for storage of a scaffold board 18. Also disclosed in a scaffolding board formed in two halves 18 for ease of storage and transportation. A further invention is also disclosed which pertains to a collapsible ladder structure having two stiles formed of telescopically collapsible tubular sections, a plurality of rungs each connected at its ends to a respective section of each stile and at least one safety rail 20, 22, 80, 82 connected to the uppermost section or sections of the stiles, wherein in the extended state of the ladder structure, the distance between each safety rail and the safety rail or rung below it exceeds the separation of the rungs.

Description

COLLAPSIBLE SCAFFOLDING TOWER

Field of the invention

The present invention relates to a collapsible scaffolding tower and also to a scaffold board and a ladder collapsible ladder structure suitable for use in such a tower.

Background of the invention

A collapsible scaffolding tower has already been proposed by the present Applicants in EP 1392940, which is believed to constitute the closest prior art to the present invention. In the known tower, the two sides of the tower are formed by telescopically collapsible ladder structures which are themselves known, for example from EP 0527766.

The sides are connected to one another by a folding gate structure which maintains the sides of the sides upright and at the required distance apart when the tower is extended.

The gate structure is formed of two leaves that are hinged to one another and to the stiles of the lowermost sections of the ladder structures. In this way, when the tower is collapsed the folded leaves lie between, and in planes parallel to, the two ladder structures.

To erect a scaffolding tower, the two sides are first pulled apart by unfolding the gate structure. The two ladder structures are next extended to form the sides of the tower.

It is however still necessary to attach further components to the erect the tower before it can be used safely. In particular, at least one scaffold board is needed to form a support platform, rails at hand and knee level are required for safety and additional braces are desirable to prevent the erected tower from racking.

In EP 1392940, such items as the scaffold board and safety rails needed to be stored and transported separately, which detracted from the ease of use of the tower.

Object of the invention The present invention seeks therefore to provide a modification of the collapsible scaffolding tower taught by EP 1392940 which allows most, if not all, of what is needed to erect a functioning tower to be collapsed into one neat self-contained package.

Summary of the invention

In accordance with a first aspect of the invention, there is provided a scaffolding tower comprising two telescopically collapsible ladder structures defining the sides of the tower, and a folding gate structure for maintaining the sides of the tower apart, the gate structure being formed of two leaves that are hinged to one another and to the stiles of the lowermost sections of the ladder structures so that the leaves may be folded to lie in planes parallel to the two ladder structures when the tower is collapsed, wherein the gate structure includes offset hinges arranged in such a manner as to leave a space between the two sides of the tower when in the collapsed state for storage of a scaffold board.

In a preferred embodiment of the invention, the leaves of the gate structure are connected to the stiles of the lowermost sections of the ladder structure by hinges of which the pivot axis is offset from the plane of the leaves, such that, in the collapsed state of the tower, gaps are created between the ladder structures and the leaves of the gate structure sufficiently wide to accommodate a scaffold board.

In this case, the leaves of the gate structure will be in contact with one another when the tower is collapsed but there will be spaces on both sides of the folded leaves to accommodate a scaffold board.

To fit within these spaces, a scaffold board may be formed of two halves that are connected to one another by a hinge in which the pivot axis is offset from the plane of the board, whereby in the folded state of the scaffold board, the two halves lie in planes parallel to one another but spaced apart by a gap sufficiently wide to permit the two halves of the scaffold to straddle the leaves of the gate structure.

As an alternative, a scaffold board may be formed of two separable halves of which the ends can be overlapped and interlocked to form a rigid board. In such a construction, it is possible to pivot each half of the scaffold board permanently to a rung of one of the ladder structures.

In a further embodiment, the leaves of the gate structure may be pivoted to each other using an offset hinge. In this case, a space would be created between the leaves when the tower is collapsed to accommodate a scaffold board. Thus one would not need to resort to an offset hinge in the scaffold board to straddle the folded gate structure.

Advantageously, telescopically collapsible braces may be pivotably mounted on the scaffold board which, when extended, can be connected at an angle between the ladder structures and the scaffold board to increase the weight bearing capacity of the scaffold board and assist in preventing the tower from racking.

It is important when working on a tower that anything dropped accidentally should not be able to roll off a scaffold board and cause possible injury to a person standing at the bottom of the tower. This may be achieved by providing the halves of the scaffold board with hinged kick plates that can be raised into an upstanding position to act as a safety fence.

Kick plates are only strictly required along the longer edges of the scaffold board but it is preferred for them to be present around the entire periphery of the scaffold board. In such a case, it is possible to arrange for the kick plates to interlock with one another at each corner to create a stable safety fence around the entire scaffold board.

In use, an operator can climb on one of the two ladder structures to gain access to the raised platform. However, it would not always be safe to do so from outside the tower because the weight of the operator could result in toppling of the tower. Instead, the operator must climb one of the ladder structures from inside the tower, that is to say with his weight between the two sides of the tower.

To permit such use of the tower, at least one half of the scaffold board preferably includes a trap door.

The trap door is preferably hinged along a hinge line extending parallel to the longer dimension of the scaffold board.

EP 1392940 further required safety rails to be stored and transported separately. While the rungs of the upper sections of the ladder structures could act as side safety rails, separate safety rails were needed front and back.

In a preferred embodiment of the invention, telescopically collapsible safety rails are releasably secured to collars mounted on upper stiles of the ladder structures, the safety rails being connectable to collars on the same ladder structure in the collapsed state of the tower and being extendable and connectable to one ladder structure at one end and to the other ladder structure at the other end in the erected state of the tower.

In this way, the safety rails store and stack between the rungs of the ladder structures in the collapsed state of the tower but serve as front and back safety rails when the tower is erected.

Whereas the rungs of the ladder section need to be relatively closely spaced to enable an operator to climb onto the support platform, the stile sections attached to the safety rails need to be relatively widely spaced apart.

If the same rung spacing is retained, there will be more safety rails than necessary which results in additional cost and also in a reduction in the diameter of the stile sections attached to the top safety rail.

Advantageously, in each ladder section, the lowermost stile section is of greater length than all the remaining stile sections and the uppermost three stile sections have a length greater than all the lower stile sections. In this way, all the stile sections can collapse into the lowermost stile section. However, the top two stile sections which carry safety rail attachment collars are capable of being separated from one another and from the top rung by a distance exceeding the separation between all the remaining rungs when the ladder structure is fully extended.

The top three sections require longer stile sections even though only two sections have a greater extension because each stile section must remain entirely enclosed within the one beneath it when the ladder structure is collapsed. Whereas stops limiting the extension of the top two stile sections are arranged near the lower end the stile sections, in the case of the third stile section from the top its stop must be arranged further up the stile to maintain the extent that the attached rung can be raised within the limits permissible for all the rungs of a ladder structure.

In accordance with a second aspect of the invention, there is provided a scaffold board formed in two halves for ease of storage and transportation.

In accordance with a third aspect of the invention, there is provided a collapsible ladder structure having two stiles formed of telescopically collapsible tubular sections, a plurality of rungs each connected at its ends to a respective section of each stile and at least one safety rail connected to the uppermost section or sections of the stiles, wherein in the extended state of the ladder structure, the distance between each safety rail and the safety rail or rung below it exceeds the separation of the rungs.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which Figure 1 is a perspective view of a scaffolding tower of the present invention in an erected state, Figure 2 is a perspective view of the scaffolding tower of Figure 1 shown in a collapsed state, Figure 3 is a side view of the scaffold board of the scaffolding tower of Figures 1 and 2, shown in its collapsed state, Figure 4 shows the scaffold board of Figure 3 in a partially unfolded state, Figure 5 shows the scaffold board of Figures 3 and 4 in a fully unfolded state and with its trap door raised, Figure 6 is a perspective view of a safety rail of the tower shown in Figures 1 and 2, Figure 7 shows an alternative design for a quickly releasable coupling between a safety rail and a stile collar, and Figure 8 is a schematic section through one of the stiles of one of the ladder structures of the tower shown in Figure 1 when in the fully collapsed position.

Detailed description of the preferred embodiment

The scaffold tower 10 shown in Figures 1 and 2 comprises two substantially identical ladder structures 12 and 14 which constitute the two sides of the tower 10. The ladder structures are interconnected at their lower end by a folding gate structure 16 made up of two leaves 16a and 16b.

At their upper ends, the sides 12 and 14 are connected to one another by a scaffold board 18 and upper and lower safety rails 20 and 22. To prevent racking, braces 24 extend between the ladder sections 12 and 14 and the scaffold board 18. The feet of the ladder sections 12 and 14 are fitted with wheels 26 to permit the entire scaffold to be moved both when erected and when collapsed.

Additionally, each foot has an outrigger 28 that is pivotable about the vertical central axis of the stile and is fitted at its outer end with a shoe 30 on an adjustment screw 32. The four outriggers 28 can be pivoted to fit under the lowermost rung when the tower is collapsed, as shown in Figure 2, or they can be pivoted out as shown in Figure 1 to extend the area of the base of the tower and increase its stability. The outriggers 28 can be set at any desired angle for maximum stability and the adjustable shoes enable the tower 10 to be erected vertically even when standing on uneven ground.

To mount on to the scaffold board 18, a person must climb up the ladder structure 12 from inside the tower, to avoid any risk of its toppling. A trap door 34 in the scaffold board 18 is hinged upwards to allow the person to reach the level of the scaffold board and is then closed.

When standing on the scaffold board 18, the person can work securely above ground level with safety rails all around the tower to avoid any risk of falling off. Additionally, kick plates 36 around the scaffold board 18 ensure that anything dropped onto the scaffold board cannot accidentally roll off and injure someone below.

In the illustrated preferred embodiment of the invention, all the components of the erected tower shown in Figure 1 can be collapsed into the self-contained package shown in Figure 2. This allows the entire tower to be transported in the back of a small commercial vehicle without any risk of it being discovered upon arrival on site that some components of the tower are missing.

The scaffold board 18 and the ladder structures are the only two parts that are separable completely from one another. All the remaining components, namely the gate structure 16, the safety rails 20 and 22 and the outriggers 28 remain attached to the ladder structures 10 and 12 when the tower is collapsed.

Description of the ladder structures

Each of the ladder structures 12 and 14 is constructed in the same way as a conventional telescopically collapsible ladder. Only the components of the ladder structure 14 have been given reference numerals in Figure 1 as the two sides of the tower 10 are mirror images of one another.

The ladder structure 14 has two vertical stiles 50 and 52 made up of sections of progressively reducing diameter, designated 50a to 50g and 52a to 52g that collapse telescopically into one another. The rungs 60, 62 and 64 are all connected to the lowermost section, for example 50a, of each stile, this being the section with the largest diameter and also the longest section. These rungs 60, 62 and 64 cannot move relative to one another and the reason that there are three rungs on the lowermost stile section 50a is both to give additional rigidity to the ladder structure 14 and to maintain the gap between rungs within acceptable limits.

The next four rungs 66, 68, 70 and 72 are each connected at their opposite ends to respective sections of the two stiles. Thus the rung 66 is connected to the section designated 50b and 52b, rung 68 to section 50c and so on. As can be seen from Figure 2, these rungs can be collapsed against one another when the tower is collapsed by telescoping the stiles 52 and 54.

The stile sections are locked relative to one another when the tower is erected by means of retractable bolts (not shown) operated by levers mounted on the front or on the underside of each rung. These bolts extend into aligned holes in the tubular sections of the stiles to lock them relative to each other. The bolts are spring biased and engage automatically when each ladder structure is extended.

They can either be retracted manually to collapse the ladder structure or they may be retracted automatically as taught by EP 0527766.

Instead of being attached to a rung, each of the top two sections 50f and 50g of each stile is attached to a fixed side safety rail 80, 82 and a front or back safety rails 20,22.

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Description of the gate structure

The gate structure 16 is formed of two leaves 16a and 16b that are hinged to one another. At their ends, the leaves 16a and 16b are pivotably connected to the rear stiles of the two ladder structures 12 and 14 by offset hinges 16c. The pivot axis of each hinge 16c is the vertical central axis of the respective stile. Thus, the pivot axis of each hinge 16c is offset from the plane of the leaf 16a or 16b so that when erected the gate 16 lies behind the plane containing the axes of the rear stiles of the two ladder structures.

This use of offset hinges is important when the tower is collapsed because, as shown in Figure 2, there will be a gap between each collapsed ladder structure 12, 14 and the adjacent leaf 16a or 16b of the folded gate structure. The width of the gap will be equal to the offset of the hinges 16, i.e. the length of the hinge arm connecting the leaf of the gate structure to the rear stile of the ladder structure. The gaps created by the offset hinges 16s allow a folded scaffold board to be housed between the collapsed ladder structures and the folded gate structure, as shown in Figure 2.

Description of the scaffold board

For the scaffold board to fit in these gaps, it can itself be made with an offset central hinge as shown in Figures 3 to 5. In this case, the offset hinge 18c creates a gap between the two halves of the scaffold board 18 when it is folded (as shown in Figure 3) to straddle the folded gate structure 16.

It will be appreciated that as an alternative to the use of offset hinges on both the gate structure 16 and the scaffold board 18, it would be possible to connect the two -11 -leaves 16a and 16b of the gate structure 16 to one another using offset hinges. In this case, a gap will be present between the leaves 16a and 16b in the collapsed state of the tower which can be used to accommodate a folded scaffold board using a conventional hinge.

The two halves of the scaffold board need not be permanently hinged to one another but can could be entirely separable. In this case, they can be stored separately in the gaps present between the ladder structures when the tower is collapsed. It is also possible to pivot each of the halves of the scaffold board 18 to one of the rungs of one of the ladder structures. The total combined length of the two halves of the scaffold board can be longer than the gate structure and their overlapping ends can be designed to interlock. Thus to erect the scaffold board, the two halves are pivoted individually beyond their horizontal position and their interlocking formations are meshed with one another as they are simultaneously lowered into the horizontal position.

Regardless of whether the scaffold board has hinged or separable halves, it is desirable for it to include kick plates to act as a safety fence and a trap door. Figures 4 and 5 show how these components can be integrated into a scaffold board having an offset hinge but it will be clear that these components can readily be incorporated into a scaffold board having a different construction.

As shown in Figure 4, the scaffold board 18 is formed in two halves 18a and 18b that are connected to one another by an offset hinge 18c. Kick plates 36a, 36b are pivoted by hinges 94 to the front edges of the halves 18a and 18b.

Further plates 36c and 36d are pivoted to the side edges and 36e and 36f to the rear edges. Because of the hinges 94, the kick plates can either be folded to lie against the scaffold board for storage and transportation, as shown for the -12 -plates 36a, 36c and 36e attached to left half 18a of the board in Figure 4, or they may be raised into a vertical position, as shown to the right in Figure 4 and in Figure 5, to form a safety fence. The kick plates may be designed to engage with one another at the corners to remain in the vertical position.

The right half of the scaffold board, as shown in Figure 5, is formed as an open frame with a trap door 34 that is pivoted about hinges 98. This allows the trap door to be raised in the manner shown in Figure 1 to enable a person to mount onto the scaffold board. When the trap door 34 is lowered, as shown in Figure 4, it rests on the frame and provides a stable platform on which a person can stand.

As shown in Figure 3, but omitted from Figures 4 and 5, braces 24 are pivotably attached to the halves of the scaffold board which are extended and connected to the ladder structures, as shown in Figure 1, after the scaffold board has been mounted on the tower. The braces may act in tension only but it is preferred for them to be lockable in their extended state so that they may additionally act in compression to resist racking.

Description of the safety rails

Two safety rails are arranged on each of the top two stile sections of the two ladder structures. The lower of these two safety rails, for example those designated 80 and 82 in Figure 1, are permanently attached to the stile sections and incorporate release bolts for locking the stile sections in their extended position. For all intents and purposes, these safety rails 80 and 82 are designed in the same way as the remaining rungs.

The upper of each of the two safety rails, designated and 22 in Figure 1, is designed as shown in Figure 6. In -13 -particular, each of these rails is made up of three telescoping sections 22a, 22b an 22c so that the rail can be lengthened and shortened. Furthermore, one end of each of these safety rails is designed to it they can be connected and disconnected from a collar 97a secured to one of the stile section.

When the tower is collapsed, each of the rails 20 and 22 is collapsed and its ends are connected to collars on the same ladder structure, as shown in Figure 2. In this way, all the safety rails stack above the rungs of the ladder structure. When the tower is erected, on the other hand, one end of each safety rail is disconnected from a collar 97a on its own ladder structure and connected instead to a collar 97a on the other ladder structure, the rail being extended as necessary in the process. In this way, the safety rails and 22 above the side rails can be repositioned to act as front and back safety rails, as shown in Figure 1.

Figure 7 shows an alternative coupling between a collar 197 and a safety rail 122. In this case, the collar is formed with a radial projection having a slot 126 of keyhole section. In other words, the slot 126 comprises a narrow channel which widens at its based into a cylindrical opening. A pin 124 rotatably mounted in the end of the rail 122 is cylindrical but has two flats. To connect the rail 122 to the collar 197, the pin 124 is first rotated by manually turning it head 128 so that the flats lie in vertical planes. In this orientation, the pin 124 can be inserted into the slot 126 as the flats allow it to pass through the narrow channel. On reaching the base of the slot, the pin 124 is rotated so that the flats lie horizontally and prevent the pin 124 from being withdrawn from the slot 126. A detent (not shown) may cooperate with the head 128 to retain the flats in a horizontal position to prevent accidental withdrawal of the pin 124 from the slot 126.

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Description of the stile sections

As can be seen from Figure 1, the distance between the safety rails 20 and 22 needs to be greater than the distance between the rungs 66 to 72. Hence, the stile sections 50f and 50g need to be extendable by a greater distance than all the remaining stile sections. This however presents a problem on account of the manner in which the stile sections are constructed.

As shown in Figure 8, which is a section through the stile 50 when the tower is collapsed, each of the stile sections 50a to 50g has holes 102a to 102g near its lower end. These holes are used to locate a plastics spacer collar (not shown) around the outside of the stile section.

The spacer collar serves to provide a close fit between the sections to prevent the stiles from bending then they are extended and it also serves to limit the extent that the stile section can be extended.

It is essential to ensure that, when a ladder structure is collapsed, the spacer collars always remain within the next lower section. If allowed to protrude beyond the end of the next lower section, the spacer collar would fall off.

If all the section 50a to SUe were to be made short and only the sections 50f and 50g attached the safety rails made longer, the collar on the section 50f would be able to fall off its stile section when the ladder structure is fully collapsed. To overcome this problem, the section SUe is also made longer but its maximum extension is limited by placing its collar locating holes 102e further from its base.

Claims

-15 -CLAIMS1. A scaffolding tower comprising two telescopically collapsible ladder structures defining the sides of the tower, and a folding gate structure for maintaining the sides of the tower apart, the gate structure being formed of two leaves that are hinged to one another and to the stiles of the lowermost sections of the ladder structures so that the leaves may be folded to lie in planes parallel to the two ladder structures when the tower is collapsed, wherein the gate structure includes offset hinges arranged in such a manner as to leave a space between the two sides of the tower when in the collapsed state for storage of a scaffold board.
2. A scaffolding tower as claimed in claim 1, wherein the leaves of the gate structure are connected to the stiles of the lowermost sections of the ladder structure by hinges of which the pivot axis is offset from the plane of the leaves, such that, in the collapsed state of the tower, gaps are created between the ladder structures and the leaves of the gate structure sufficiently wide to accommodate a scaffold board.
3. A scaffolding tower as claimed in claim 1, wherein the leaves of the gate structure are pivoted to each other using an offset hinge, thereby creating a space between the leaves when the tower is collapsed to accommodate a scaffold board.
4. A scaffolding tower as claimed in claim 2, further comprising a scaffold board formed of two halves that are connected to one another by a hinge in which the pivot axis is offset from the plane of the board, whereby in the folded state of the scaffold board, the two halves lie in planes parallel to one another but spaced apart by a gap sufficiently wide to permit the two halves of the scaffold -16 -to straddle the leaves of the gate structure when the tower is collapsed.
5. A scaffolding tower as claimed in claim 2 or 3, further comprising a scaffold board formed of two separable halves of which the ends can be overlapped and interlocked to form a rigid board.
6. A scaffolding tower as claimed in claim 5, wherein each half of the scaffold board is permanently pivoted to a rung of one of the ladder structures.
7. A scaffolding tower as claimed in any one of claims 4 to 6, wherein telescopically collapsible braces are pivotably mounted on the scaffold board which, when extended, can be connected at an angle between the ladder structures and the scaffold board to increase the weight bearing capacity of the scaffold board and assist in preventing the tower from racking.
8. A scaffolding tower as claimed in any one of claims 4 to 7, wherein the halves of the scaffold board are provided with hinged kick plates that can be raised into an upstanding position to act as a safety fence.
9. A scaffolding tower as claimed in claim 8, wherein kick plates are provided around the entire periphery of the scaffold board.
10. A scaffolding tower as claimed in claim 9, wherein the kick plates engage with one another at each corner to create a stable safety fence around the entire scaffold board.
11. A scaffolding tower as claimed in any one of claims 4 to 10, at least one half of the scaffold board includes a trap door.

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12. A scaffolding tower as claimed in claim 11, wherein the trap door is hinged about an axis lying parallel to the longitudinal dimension of the scaffold board.
13. A scaffolding tower as claimed in any preceding claim, wherein telescopically collapsible safety rails are releasably secured to collars mounted on upper stiles of the ladder structures, the safety rails being connectable to collars on the same ladder structure in the collapsed state of the tower and being extendable and connectable to one ladder structure at one end and to the other ladder structure at the other end in the erected state of the tower.
14. A scaffolding tower as claimed in any preceding claim, wherein, in each ladder section, the lowermost stile section is of greater length than all the remaining stile sections and the upper stile sections have a length greater than all the lower stile sections.
15. A scaffolding tower constructed and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
16. A scaffold board formed in two halves for ease of storage and transportation.
17. A scaffold board as claimed in claim 16 wherein the two halves of the scaffold board are pivotably connected to one another.
18. A scaffold board as claimed in claim 17, in which the two halves of the board are connected to one another by a hinge in which the pivot axis of the hinge is offset from the plane of the board, to create a gap between the halves of the board when in a folded state.

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19. A scaffold board as claimed in claim 16, wherein the two halves of the board are separable and have along their adjacent edges overlapping and formations that interlock to permit the board to support weight when resting horizontally on a scaffolding tower.
20. A scaffold board as claimed in any of claims 16 to 19, wherein at least one of the halves of the board is fitted with a trap door.
21. A scaffold board as claimed in claim 20, wherein the trap door is hinged about a hinge line parallel to the longer dimension of the board when in use.
22. A scaffold aboard as claimed in any of claims 16 to 19, wherein kick plates are pivotable mounted around edges of the board for movement between a stacked position in which they lie parallel to the board and a deployed position in which they lie normal to the board and form a fence to prevent articles from rolling off the board.
23. A collapsible ladder structure having two stiles formed of telescopically collapsible tubular sections, a plurality of rungs each connected at its ends to a respective section of each stile and at least one safety rail connected to the uppermost section or sections of the stiles, wherein in the extended state of the ladder structure, the distance between each safety rail and the safety rail or rung below it exceeds the separation of the rungs.
24. A collapsible ladder structure as claimed in claim 23, wherein the uppermost stile sections connected to safety rails and the stile sections connected to the uppermost rung all have a length greater than the length of the remaining stile sections.-19 -
25. A collapsible ladder structure as claimed in claim 24, wherein the lower ends of the stile sections are fitted with spacer collar to guide the sections within one another and to limit the extension of each stile section, and wherein the spacer collars fitted to the stile sections connected to the uppermost rung are arranged at a greater distance from the lower end of their stile sections than the spacer collars of all the remaining stile sections.