GB2413148A

GB2413148A - Loft ladder assembly

Info

Publication number: GB2413148A
Application number: GB0408475A
Authority: GB
Inventors: Per-Olof Eriksson; Christer Johansson
Original assignee: Telesteps AB
Current assignee: Telesteps AB
Priority date: 2004-04-16
Filing date: 2004-04-16
Publication date: 2005-10-19
Also published as: EP2102429B1; JP2007532809A; US20070234654A1; WO2005100716A1; CN100447371C; ATE519000T1; NZ550323A; ES2370645T3; AU2005233496A1; CA2562409C; AU2005233496B2; DK2102429T3; EP2102429A1; GB0408475D0; CA2562409A1; CN1997800A

Abstract

A loft ladder assembly (10) which comprises a telescopically collapsible ladder (12) and frame (14) for mounting the ladder (12) within a hatch opening. The frame (14) comprises mounting bracket (14a) to be secured in use to the hatch opening, to which bracket (14a) the uppermost section of the ladder (12) is pivotably connected, and carriage (14b) pivotably connected to the mounting bracket (14a) for supporting the wight of the ladder (12) in its stowage position and preventing it from extending unintentionally. The frame (14) may have hooks (22) for receiving lugs (24) projecting laterally from the lowermost section of the ladder (12). The carriage (14b) may be connected to the mounting bracket (14a) by at least one toggle spring (16a) urging the carriage into stowage position and away from the ladder respectively when collapsing or extending the ladder (12). The rungs can have locking pins with biassing springs which push the pins laterally into holes in the stiles of the ladder (12).

Description

LOFT LADDER ASSEMBLY

The present invention relates to a loft ladder assembly.

Hatch doors are commonly provided in a ceiling to allow access to the loft or roof space of a building. Loft ladders are also known which are stored in the roof space and which are deployed by being pulled down after the hatch door has lo been opened.

Conventional loft ladders are usually of the expendable type. By this it is meant that the ladder is formed of two (or sometimes three) ladder sections arranged in different planes, which can slide over one another and can be locked to each other in a stacked and in an extended position. Even after the sections have been stacked, they are longer than the hatch door. Consequently, to stow away the ladder, it has first to be raised into the loft and then pivoted for its lower end to be able to pass through the hatch. The stacked ladder is normally pivoted about an axis which is near its centre so that the ladder is nearly balanced. As a result, the ladder tends to stay in its horizontal position in the loft when the hatch door is opened and, to deploy it, a user must first pivot its lower end of the hatch and then releases its various catches manually to allow it to be extended to reach the floor.

Because such ladders are not very compact, even in their stacked condition, they have the disadvantage of taking up roof space. It is therefore preferable to form the ladder as a telescopically collapsible ladder where the stiles are formed of sections that collapse into one another, as described for example in EP 0527766. Such a ladder is more compact than an expendable ladder when it is collapsed and can be made sufficiently small to fit entirely within the hatch opening. r - 2 -

However, if the top rung of a telescopically collapsible ladder is pivoted on one side of the hatch opening, it will tend to drop and extend itself under the action of its own weight as soon as the hatch door is opened. This could cause injury to an unsuspecting user.

The present invention seeks therefore to provide a loft ladder assembly that can fit within a hatch opening without taking up loft space but can be deployed and stowed away lo simply and safely.

According to the present invention, there is provided a loft ladder assembly which comprises a telescopically collapsible ladder in combination with a frame for mounting IS the ladder within a hatch opening, the frame comprising a mounting bracket to be secured in use to the hatch opening, to which bracket the uppermost section of the ladder is pivotably connected, and a carriage pivotably connected to the mounting bracket for supporting the weight of the ladder in its stowage position and preventing the ladder from extending unintentionally.

To prevent the ladder from extending under the action of its own weight, the carriage may be provided with means for releasably engaging the lowermost section of the ladder.

The latter means may suitably comprise a pair of hooks for receiving lugs projecting laterally from the lowermost section of the ladder.

Preferably, the carriage is connected to the mounting bracket by means of at least one spring urging the carriage into the stowage position against the action of the weight of the ladder. Conveniently, each spring should be connected to the mounting bracket and the carriage in such a manner as to act as an over-centre toggle spring, so as to urge the carriage away from the ladder when the latter is deployed. - 3

The collapsible ladder is preferably constructed in the manner taught by EP 0527766. In particular, the ladder may have locking pins built into the rungs that are spring biases to move laterally outwards into holes formed in the stiles to lock the sections of the stiles together when the ladder is in its extended position, the locking pins for the next higher section of the ladder being retracted as the rung carrying the locking pins approaches the rung beneath it. When constructed in this manner, the ladder will open naturally from the top down when its lowermost section is released from the carriage and it will collapse in sequence from the lowermost section up as it is raised into its stowage position.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a loft ladder assembly of the present invention it its stowage position, Fig. 2 is a front view of the loft ladder assembly in Fig. 1 with the carriage lowered into a vertical position, Fig. 3 is a side view of a detail of the loft ladder assembly in the same position as shown in Fig. 2, and Fig. 4 is a view similar to that of Fig. 3 with the ladder in its deployed position.

The loft ladder assembly 10 shown in Figure 2 comprises a telescopically collapsible ladder 12 and a frame 14 for mounting the ladder in a hatch opening. The frame 14 is formed of a mounting bracket 14a and a carriage 14b pivotable relative to the mounting bracket 14a between a horizontal position shown in Fig. 1 and a vertical position shown in Figs. 2, 3 and 4. Two coil springs 16a and 16b act as toggle springs, as will be described below, to spring bias the carriage 14b into its two end positions. - 4

The ladder 12 is constructed in the same manner as a conventional telescopic ladder which is currently commercially available under the trademark Telesteps.

Whilst such a construction of the ladder is preferred, it is not fundamental to the present invention and it will not therefore be described in detail in the present context. For further details on the internal construction of the ladder 12, reference may be made to EP 0527766.

lo The Telesteps ladder is preferred because it collapses from the bottom upwards and not from the top downwards. In particular, the ladder has locking pins built into its rungs, which are spring biased to move laterally outwards into holes formed in the stiles in order to lock the sections of the stiles together when the ladder is in its extended position. As two rungs come together, the lower rungs presses on two levers 26 (see Fig. 4) which depend from the upper rung to cause the locking pins formed in the upper rung to be retracted from the stiles. This now allows the next higher section of the ladder to be collapsed and the process repeats until all the sections are collapsed from bottom upwards.

Each of the rungs of the ladder have two laterally projecting lugs 24 which engage in hooks 22 projecting from the carriage 14b. After the ladder has been fully collapsed, the lugs 24 lowermost rung can be lifted onto the hooks 22 and this prevents the ladder from extending under the action of its own weight.

The uppermost section of the ladder is pivoted relative to the mounting bracket 14a about pins 28 passing two limbs that project from the mounting bracket 14a. Similarly, the carriage 14b is pivoted about pins 18 passing through two short ears 30 that project from the mounting bracket 14a. - 5

The springs 16a and 16b are connected to bracket 14a and the carriage 14b in such a manner that as the carriage pivots downwards from the horizontal position shown in Fig. 1 to the vertical position shown in Fig. 2, it passes through an over centre position in which the ends of the spring and the pivot pins 18 lie in a straight line. In this position, the length of the spring is maximum and a force has to be applied to the carriage to move the carriage towards this position, as the position is approached in either direction. In other words, the springs 16a and 16b have a toggle action forcing the carriage 14b away from the over centre position. The carriage is thus stably held by the springs 16a and 16b in both the horizontal and the vertical position.

In use, the ladder assembly is fixed by securing the mounting bracket 14a by bolts or screws to the ceiling joists surrounding and defining the hatch opening. When the hatch door (not shown) is opened by being hinged or removed, the loft ladder assembly will be found in the hatch opening in its configuration shown in Fig. 1. In this state, the springs apply a moment to the carriage 14b which is slightly greater than the moment of the combined weights of the ladder 12 and the carriage 14b, so that the loft ladder assembly will remain in the hatch opening after the hatch door has been opened.

To deploy the ladder, the carriage 14b is pivoted downwards against the action of the springs 16a and 16b by pulling down on a strap 32. This operation does not require much effort because of the leverage afforded by the carriage 14b. The carriage is pivoted past the over centre position to the position shown in Figs. 2 and 3, from which it will be seen that the line of action of the springs 16a and 16b has moved to the opposite side of the pins 18 so that the carriage 14b will now remain stably in its vertical position without assistance from the weight of the ladder 12.

As can be seen from Figs. 2 and 3, when the ladder is stowed away, there remains a distance between its top two rungs. This allows the user to lift the entire ladder and thereby disengage the lugs 24 from the hooks 22. Once the weight of the ladder 12 is no longer supported by the hooks 22, it will extend naturally from the top down as can be seen from Fog. 4. This allows the user to pull the ladder 12 away from the carriage 14b and to extend until it reaches the ground and is inclined at a safe and comfortable angle.

To stow away the ladder, the above procedure is essentially reversed. First, after using the levers 26 to release the locking pins of the lowermost rung of the ladder, the lowermost section of the ladder is raised. As its rung reaches the next higher rungs, it will automatically release the locking pins of the next higher section to allow the entire ladder to be collapsed.

With all the sections of the ladder 12 collapsed against one another, the lugs 24 of the lowermost section can be raised onto the hooks 22 whereupon the weight of the ladder will be fully supported by the carriage 14b. While holding the strap 32, the carriage can now be pivoted towards its horizontal position and once it passes the over centre position the strap is used to restrain it so that it can be returned gently to its stowage position of Fig. 1.

The hatch door can then be replaced.

The person skilled in the art will appreciate that various modifications may be made to the described loft ladder assembly without departing from the scope of the invention as set out in the appended claims. For example, the carriage 14b may carry or be connected to the hatch door. Furthermore, in place of springs, one could use a catch to hold the carriage in its raised position. - 7

Claims

1. A loft ladder assembly which comprises a telescopically collapsible ladder in combination with a frame for mounting the ladder within a hatch opening, the frame comprising a mounting bracket to be secured in use to the hatch opening, to which bracket the uppermost section of the ladder is pivotably connected, and a carriage pivotably connected to the mounting bracket for supporting the weight lo of the ladder in its stowage position and preventing the ladder from extending unintentionally.

2. A loft ladder assembly as claimed in claim 1, wherein, in order to prevent the ladder from extending under the action of its own weight, the carriage is provided with means for releasably engaging the lowermost section of the ladder.

3. A loft ladder assembly as claimed in claim 2, wherein the means for releasably engaging the lowermost section of the ladder comprise a pair of hooks for receiving lugs projecting laterally from the lowermost section of the ladder.

4. A loft ladder assembly as claimed in any preceding claim, wherein the carriage is connected to the mounting bracket by means of at least one spring urging the carriage into the stowage position against the action of the weight of the ladder.

5. A loft ladder assembly as claimed in claim 4, wherein each spring is connected to the mounting bracket and to the carriage in such a manner as to act as an over centre toggle spring, so as to urge the carriage away from the ladder when the latter is deployed. - 8 -

6. A loft ladder assembly as claimed in any preceding claim, wherein the ladder has locking pins built into the rungs, which pins are spring biases to move laterally outwards into holes formed in the stiles in order to lock the sections of the stiles together when the ladder is in its extended position, the locking pins for the next higher section of the ladder being retracted as the rung carrying the locking pins approaches the rung beneath it.

lo

7. A loft ladder assembly constructed and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.