GB2418702A

GB2418702A - Telescopic loft ladder

Info

Publication number: GB2418702A
Application number: GB0421595A
Authority: GB
Inventors: James Thomas Weston; Richard Weston
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-09-29
Filing date: 2004-09-29
Publication date: 2006-04-05
Also published as: GB0421595D0

Abstract

A loft ladder assembly comprises a telescopic ladder (20) attached at the upper end of each stile to a lever arm (22) which in use is pivotally connected to one side of a loft hatch (10). Preferably the lever arm assemblies are in the form of sprung hinges (Figures 3 and 4), to support the weight of the ladder as it is moved into an in use position. Preferably the upper end of each stile includes a plurality of axially and circumferentially spaced holes (52 Figure 5) which engage with spring clips to allow the effective length of the ladder to be adjusted.

Description

24 1 8702 - 1

LOFT LADDER ASSEMBLY

Field of the invention

The present invention relates to a telescopically collapsible loft ladder assembly.

Background of the invention

Telescopically collapsible ladders, which are in themselves well known, essentially comprise two stiles made up of telescopically collapsible sections and each rung of the ladder is connected at its opposite ends to the top of one of the sections in each stile. Latches are provided in each rung to lock the stiles in their extended position.

The construction of one such ladder is described in European Patent 0527766 which teaches automatically releasing the latch of a rung as it contacts the rung beneath it, so that the ladder is collapsed from the bottom upwards. Ladders constructed in this manner are commercially available under the brand name Telesteps.

It has previously been proposed to use a telescopically collapsible ladder as a loft ladder. GB Patent No. 2263932 teaches that a telescopically collapsible ladder can be made sufficiently short to pass through the loft access hatch and to lie, when stored in the loft, only within the floor area of the loft occupied by the access hatch. In practice, however, installation of such a loft ladder requires the access hatch to be enlarged because the ladder will not fit through a standard hatch.

Co-pending British Patent Application No. 0408475.2 teaches mounting a collapsible ladder in a loft using a frame with a sprung carriage that supports the weight of the ladder when it is stowed in the loft and once again the access hatch often needs to be enlarged to accommodate the frame because it will not fit in standard hatches.

In prior attempts at using a telescopically collapsible ladder to gain access to a loft, the top sections of the stiles of the ladder was pivotably mounted at a point fixed to one side of the access hatch. The minimum size of the access hatch was therefore dictated by the collapsed length of the ladder. This length is itself predetermined by the specified distance between the rungs when the ladder is extended (often set by safety standards) and the number of rungs needed to reach from the ceiling to the ground. For these reasons, if the hatch was too short for the collapsed ladder to pass through, the only solution was to enlarge the loft access hatch. As this is not a simple task, it made selfinstallation of a telescopic loft ladder impossible for most home owners.

Object of the invention The present invention seeks therefore to provide a telescopic loft ladder that can be mounted in a hatch that is shorter than the collapsed length of the ladder.

Summary of the invention

According to the present invention, there is provided a loft ladder assembly comprising a telescopically collapsible ladder of which the uppermost section of each of the stiles is connected to one end of a lever arm of which the other end is pivotably mountable on one side of the access hatch.

The lever arm to which the upper end of the collapsible ladder is connected can in the present invention pivot about its other end as the loft ladder is raised and thereby carry the upper end of the ladder into the loft space as it is stowed away. Therefore, unlike GB 2263932, when the ladder - 3 is stored in the loft, it cannot lie only within the floor area of the loft occupied by the access hatch. However, the length of the collapsed ladder may now be longer than the access hatch by an amount equal to the length of the lever arm, which preferably can move to a substantially horizontal position in the loft when the ladder is stowed away.

Preferably, each lever arm forms one leaf of a hinge of which the other leaf is securable to a joist running along lo said one side of the access hatch.

The hinges may conveniently incorporate springs acting to counterbalance the weight of the ladder.

Another problem encountered when using a telescopic ladder as a loft ladder results from the fact that telescopic ladders need to be fully extended when in use.

Hitherto, it was necessary to provide a wide range of ladders to suit different ceiling heights. Because the ladder heights needed to be available in increments smaller than distance between the rungs, it did not suffice to provide ladders having different numbers of sections in their stiles.

In accordance with a second aspect of the present invention, there is provided a telescopically collapsible ladder for use in a loft ladder assembly, wherein in use the uppermost section of each of the stiles of the ladder is pivotably mounted on one side of the access hatch, characterized in that the uppermost stile sections are formed with a plurality of axially and circumferentially staggered holes for receiving spring biased latches mounted at the opposite ends of the uppermost ladder rung, whereby the fully extended length of the ladder is variable by rotating the uppermost stile sections relative to the uppermost rung before securing the stile sections to the access hatch. - 4 -

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 side view showing a telescopically collapsible ladder in its stowed position, Figure 2 is a similar view showing the ladder of Figure 1 in its extended position, lo Figure 3 is a exploded view of the hinge mechanism used to mount the telescopically collapsible ladder on one of the ceiling joists, Figure 4 shows a detail of the hinge mechanism in Figure 3, and Figure 5 is a perspective view of one of the two uppermost sections of the telescopically collapsible stiles of the ladder.

Detailed description of the preferred embodiment

In Figures 1 and 2, there is shown a hatch 10, i.e. an opening in a ceiling, that is bounded on two sides by ceiling joists 12 and 14. A hatch door 16 pivotably mounted on the joist 14 is retained by a catch (not shown) in the closed position shown in Figure 1. When the catch is released, the hatch door 16 drops under gravity by pivoting about the lower edge of the joist 14 into the position shown in Figure 2 to open the hatch 10.

A telescopically collapsible ladder, generally designated 20, has the top sections of its stiles secured to a lever arm 22 described in more detail below. The lever arm form part of a hinge mechanism and pivots about an axis defined by a shaft 24 between the position shown in Figure 1 and that shown in Figure 2. The ladder 20 is itself a conventional Telesteps, as described in detail in EP 0527766, which is incorporated herein by reference. - 5 -

The hinge mechanism supporting the ladder 20 is spring biased and as a result most of the weight of the ladder 20 and the hatch door 16 is supported when the door catch is released. The pole used to undo the catch can therefore readily be used to support the door 16 and lower it gently to its vertical position shown in Figure 2. During this time, the lower end of the ladder 20 remains supported on the hatch door by means of a pair of hooks 26 that engage in the bottom of the stiles. To extend the ladder, the lower end of the stiles is raised out of engagement with the hooks 26 and as the sections of the ladder 20 are extended by allowing them to fall under their own weight, spring biased latches in the rungs enter into holes in the stiles to lock the sections to one another and render the ladder rigid.

To stow the ladder away in the loft, the same steps are performed in reverse sequence. After manually releasing the latches carried by the lowermost ladder section, the lowermost ladder section of the ladder is raised. As it reaches the next rung, the next higher latches are released in the manner described in EP 0527766 and this is repeated until the ladder is collapsed to its minimum length. After engaging the hooks 26 in the bottom of the two stiles the weight of the ladder can be allowed to come to rest on these hooks. The hatch door 16 is now pivoted upwards and as it rises it also causes the spring biased lever arm 22 to pivot clockwise, as viewed, to pull the top of the ladder 20 into the loft. Once the door is in the position shown in Figure 1, the door catch is operated to maintain the door closed.

The effect of the lever arm 22 can readily be appreciated from Figures 1 and 2 which clearly demonstrate that the collapsed length of the ladder 20 is greater than the length of the hatch as measured between the joists 12 and 14. The difference is approximately equal to the length of the lever arm 22 which can be made as long as is - 6 necessary to permit the bottom of the ladder 20 to clear the joist 12. The lever arm 22 is connected rigidly to the uppermost sections of the ladder 20 so that it turns about the shaft 24 through the same angle as the ladder 20 itself swings, this being an angle of approximately 60 and certainly less than 90 . Hence, the arm 22 will pivot from a near horizontal attitude in the stowage position of Figure 1 to a near vertical position in the deployed state of the ladder 20 shown in Figure 2. Because it is near vertical lo when the ladder is deployed, the lever arm 22 raises the top of the ladder 20 into the loft space when the ladder is deployed which makes it easier to climb into the loft.

The hinge mechanism is shown in more detail in the exploded views of Figures 3 and 4 from which the central shaft 24 has been omitted. As shown in Figure 4, the lever arm 22 at each end of the mechanism it formed as a bracket of which the end is bent round into a tube. As an alternative, the lever arm 22 can be made by welding a flat sheet to a tube. The flat sheet is bent and a web better shown in Figures 1 and 2 is welded to the two limbs to give the lever arm the necessary rigidity to support the weight of the ladder. The lever arm 22 forms one leaf of a hinge of which the other leaf 30 is constructed in essentially the same manner but is formed with holes 32 for receiving bolts which mount the hinge mechanism to the ceiling joist 14.

Two bushes 34 which fit into the tubular portions of the two leaves of the hinge have central holes which receive the shaft 24. A coil spring 36 acts between the leaves 22 and 30 of each hinge, the spring 36 being accommodated within the tubular portions of the leaves 22 and 30 with only its free ends projecting through axial slots in the tubular portions.

The spring 36 is thus concealed within the hinge which is not only desirable aesthetically but makes for a safer construction. - 7 -

The central shaft 24 passes through a central spacer tube 38 and all the components of the hinge assembly are held together by two nuts 40 that are screwed on to threaded ends of the shaft 24.

The coil springs 36 are shaped to be relaxed when the ladder is in its stowed position and to be tensioned by the weight of the ladder as it is lowered into its deployed position. Different approaches can be adopted to bolt the hinge mechanism to the joist 14. One approach is not to connect the stiles of the ladder 20 to the lever arms 22 until after the hinge mechanism has been bolted to the joist 14. A second is to bolt the hinge mechanism with the ladder in its stowed position. Both these approaches allow the hinge mechanism to be bolted while the springs 36 are not under tension. If neither of these methods is practicable, then the second leaf 30 may need to be clamped to the joist 14 to take up the spring tension while bolts are being inserted through the holes 32.

Conventionally, each section of the stiles has only one hole to be engaged by a spring biased latch when the section is in its extended position. Once again, reference is made to EP 0527766 for an explanation of the construction and method of operation of the latches. This only allows the section to be extended to the length dictated by the position of the hole. In the case of a loft ladder, however, it is desirable to allow some adjustment of the maximum extended length of the ladder and this is made possible by the construction of the uppermost sections of stiles of the ladder shown in Figure 5. The tube 50 constituting the uppermost section has four holes 52 that are staggered both axially and circumferentially about its surface. By rotating the tube 50, different ones of the holes can be made to face the rung mounted latch so that extended length of the ladder can be adjusted to any one of four positions. - 8 -

The end of the stile section has a central threaded hole 56 for receiving a bolt to secure the stile section to the lever arm 22. In addition, the end of formed with four blind holes that cooperate with a pin projecting from the lever arm 22 to ensure that the stile section can only be mounted in the four positions in which the holes 52 are correctly aligned with the latches in the top rung. The engagement of the pin in one of the holes also ensures that the stile section 50 is not rotated accidentally once the desired maximum length of the ladder has been set. - 9 -

Claims

1. A loft ladder assembly comprising a telescopically collapsible ladder of which the uppermost section of each of the stiles is connected to one end of a lever arm of which the other end is pivotably mountable on one side of the access hatch.

2. A loft ladder assembly as claimed in claim 1, lo wherein each lever arm forms one leaf of a hinge of which the other leaf is securable to a joist running along said one side of the access hatch.

3. A loft ladder assembly as claimed in claim 2, wherein the hinge incorporates a spring acting to counterbalance the weight of the ladder.

4. A loft ladder assembly as claimed in any preceding claim, wherein the uppermost stile sections of the ladder are formed with a plurality of axially and circumferentially staggered holes for receiving spring biased latches mounted at the opposite ends of the uppermost ladder rung, whereby the fully extended length of the ladder is variable by rotating the uppermost stile sections relative to the uppermost rung before securing the stile section to the lever arm.

5. A loft ladder as claimed in claim 4, wherein the axial end of the uppermost sections of the ladder and the lever arms having cooperating formations to prevent rotation of the uppermost ladder sections relative to the uppermost rung.

6. A telescopically collapsible ladder for use in a loft ladder assembly, wherein in use the uppermost section of each of the stiles of the ladder is pivotably mounted on one side of the access hatch, characterized in that the uppermost stile sections are formed with a plurality of axially and circumferentially staggered holes for receiving spring biased latches mounted at the opposite ends of the uppermost ladder rung, whereby the fully extended length of the ladder is variable by rotating the uppermost stile sections relative to the uppermost rung before securing the stile section to the access hatch.

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