GB2429231A

GB2429231A - Ladder having anti-slip means on rails

Info

Publication number: GB2429231A
Application number: GB0517011A
Authority: GB
Inventors: Paul Anthony Eastment
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-08-19
Filing date: 2005-08-19
Publication date: 2007-02-21
Also published as: GB0517011D0

Abstract

Stability with regard to ladder use is important particularly when the ladder is used in relation to such activities as window cleaning. Unfortunately, recent use of plastic and in particular uPVC window frames renders the normal friction engagement between the ladder and the sill of a window as less reliable and therefore the potential for ladder topple and slide increases. By provision of a contact edge (22) within the rail (21) of the ladder such topple and slide movement of the ladder upon plastic window sills is resisted. The contact edge (22) may be formed of an elastomeric material e.g rubber. The contact edge (22) may be provided along the entire length of the rails (21) and may be ribbed in the direction of the rail (21).

Description

Ladder The present invention relates to ladders and more particularly to

ladders utilised with regard to window maintenance including cleaning.

The use and form of ladders is well known and generally comprises two parallel rails with rungs and treads in between them. Ladders may be extendable in order to facilitate portage of particularly long ladder lengths. It will be understood that ladders are used for a wide variety of activities and generally provide access at elevated locations on buildings and other structures.

Ladders are used by window cleaners and people wishing to maintain windows at elevated locations. Windows have traditionally taken the form of wood or steel frames in which glazing panels are located. More recently, plastic and in particularly uPVC plastic windows have become popular due to their durability and ease of manufacture. Unfortunately, the traditional approach with respect of window cleaning is leaning the ladder rungs against the sill of the window frame. This creates problems in that the sill when formed from a plastics material is generally slippery, rendering the ladder

unstable.

It will be understood that a typical ladder comprising parallel rails and rungs depends upon the weight of the rails on the ground to provide stability at that end and compressive abutment by the ladder either at the other end of the rails or at a point near to the other end of the rails in order to maintain stability. In such circumstances, the slippery nature of plastic window sills can cause problems.

Previous solutions to ladder stability have included provision of stabilisers at the base which act to expand the contact foot print of the base and also provision of stand off cages. Unfortunately, with respect to an activity such as window cleaning which requires high mobility and speed of movement of the ladder in order to quickly clean a number of windows such approaches are unacceptable. It will also be understood that window cleaning typically requires stretching to both sides of a user's reach and this may further exacerbate problems with the top part of the ladder slipping against the plastic window sill.

In accordance with the present invention there is provided a ladder comprising a rail for engaging a plastic window sill, the rail including a contact edge for engagement in use upon a sill to resist slippage relative to the sill.

Typically, the contact edge is formed from a material which locally deforms with a sill in use. Preferably, the contact edge comprises an elastomeric material. Typically, the elastomeric material is a rubber strip secured to the rail.

Generally, the contact edge extends along the whole length of the rail.

Possibly, the contact edge is ribbed in the direction of the rail.

Possibly, the contact edge has a convexed presentation surface for engagement in use with a sill. Advantageously, the convexed presentation surface is flattened upon engagement with a sill in use.

Potentially, the contact edge is secured in a groove formed in the rail through side shoulder portions of the contact edge being entrapped by a groove.

Possibly, the contact edge is removable from the rail.

Normally the rail is formed from aluminium.

Possibly, the contact edge has a broader portion at positions of the contact edge expected to be in engagement in use upon a sill edge. Possibly, the broader portion is displaceable upon the rail for different expected positions for engagement in use upon a sill edge.

Generally, the ladder comprises two parallel rails with a contact edge secured to each rail.

Also according to the present invention there is provided a contact edge for a ladder, the edge securable to a rail of the ladder for engagement in use upon a sill edge.

An embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings in which:- Fig. 1 is schematic illustration of a ladder in accordance with the present invention; Fig. 2 is a schematic cross-section illustrating securing a contact edge to a rail of a ladder; Fig. 3 is a schematic perspective view of the end of a ladder in accordance with the present invention; Fig. 4 is a schematic perspective view of a contact edge in accordance with the present invention; and Fig. 5 provides a pictorial illustration of a ladder in accordance with the present invention in use.

As indicated above, particular problems relate to use of ladders and in particular, aluminium ladders, upon plastic sills used in plastic frames and in particularly, uPVC plastic window frame windows. Essentially, the aluminium slides upon the plastic sill rendering such operations as window cleaning dangerous, particularly at high elevations of the ladder. These problems are further exacerbated when the plastic window sill is wet.

The present ladder comprises ladder rails upon which a contact edge is secure. Fig. 1 provides a schematic perspective view illustrating a ladder 1 upon which a contact edge 2 is secured. The contact edge 2 generally comprises an extruded groove section in which an elastomeric strip is secured. The groove is initially secured to the ladder rail 1 through screws 3 and then the rubber inserts secured in the groove to provide the contact edge.

It will be understood that the elastomeric strip is normally formed from a rubber material. The strip will either be compressed into the groove secured to the ladder rail or slid along its length. In either event, through compression and relatively long friction length the strip remains within the groove and so provides secure rail location. Normally, the contact edge 2 is ribbed with a rib depth of one or two millimetres.

Generally, the groove comprises an aluminium channel. The width of the channel will essentially define the width of the contact edge. It has been found that a channel width of 9mm is sufficient. The object of the contact edge is to prevent the ladder 1 slipping sideways upon window sills and therefore it will be appreciated that the width of the contact edge is important in order to achieve this objective. It will also be understood that both rails of the ladder I will normally have a contact edge secured to them.

Generally, a contact edge will be secured to the whole length of each rail of the ladder 1. Thus, the contact edge becomes engaged with a window sill at each point of contact irrespective of the lean to angle for the ladder.

Furthermore, where the ladder comprises an extending ladder by providing a contact edge upon the whole length of the rails, it will not matter where contact is made in use with a window sill along the length to which the ladder is extended, as there will always be contact between the contact edge and the widow sill.

an alternative to using screws as depicted in Fig. 1, it may be Possible to provide pegs and adhesives or other securing mechanisms for the contact edge 2 upon the rail 1.

Fig. 3 provides a schematic end perspective view of a ladder in which a contact edge 22 is integrally formed with ladder rails 21. Thus, as with a conventional ladder, the rails 21 are substantially parallel with rungs 25 between them. The contact edges 22 are provided by elastomeric strips which are secured in grooves formed in the rails 21. Although depicted with contact grooves on one side of the ladder, it will be appreciated for universality of operation, contact edges may be provided on both sides of the ladder rails 21.

The contact edges 22 as described previously will generally extend upon the whole length of the ladder rails 21. The contact edges 22 will each comprise the elastomeric strip which runs in the grooves in the rails generally formed by an extrusion process. The elastomeric strip of the contact edge 22 will generally extend beyond its groove by 2mm in order to engage a window sill in use. It is understood that the contact edges rest upon a window sill at any height engageable by the ladder and therefore, prevent any sideways slippage of the ladder on the window sill.

Whether secured in a groove element itself secured to a ladder rail or integrally formed as depicted in Fig. 3, it will be understood that the elastome,-jc strip can be removed and replaced as required. It will be understood that the elastomeric strip will generally be compressed and deform upon engagement with the window sill and therefore over a period of time at least certain portions of the contact edge 22 at the Positions of expected or repeated contact with a window sill will become worn in comparison with other parts of the contact edge 22.

Fig. 4 provides a schematic illustration of an elastomeric insert strip to form the contact edge of the present invention. Thus, the strip 31 comprises shoulder portions 32 to engage the grooves of the rail and a central contact portion 33 which will stand proud of the rail in order to engage a window sill in use. The contact portion 33 will generally include ribs to further facilitate engagement with the window sill and so prevent sideways slide on a window sill.

It will be understood that the particular problem with plastic window sills is difficult to resolve in that penetrative means for retaining location of the ladder upon the window sill such as studs or inclusion of surface spikes may damage the plastic of the window sill and at least diminish its aesthetic appearance. In such circumstances, the present contact edge is generally formed from an elastomeric material and typically rubber which is arranged such that there is no damage to the window sill. Generally, the contact edge being elastomeric will slightly deform upon engagement with the window sill and so enter into a robust engagement preventing sideways slippage.

As indicated above, aesthetic appearance and reduction of any damage to the window sill is important. In such circumstances, if there is a possibility of smearing the elastomeric strip may be formed from the transparent material or have a colour sympathetic with the window frame colour. In such circumstances as indicated above, different contact edges on either side of the ladder may have different colours so that any material smearing upon the window by engaging with the contact edge is of a colour similar to that of the window frame.

In order to further enhance the present engagement between the contact edge and the window sill, it will be understood that the elastomeric material may be presented in a slightly COnvexed arc within its retaining groove. In such circumstances upon engagement with the window sill, this convexed presentational surface of the contact edge will be flattened and so slightly envelope the window sill for greater engagement and resistance to sideways motion, it will also be understood that the flattening of the elastomeric insert will push shoulder portions into the groove and enhance engagement and resistance to lock the elastomeric material in the groove and so provide greater retention.

As indicated above, there are great benefits with regard to providing a contact edge upon the whole length of the ladder rail. This ensures that no matter what position the ladder engages upon the window sill, the contact edge will engage with that window sill and so resist sideways slewing of the ladder in use. However, in normal operation, there will be a predictable proportion of the ladder rail length that will engage the window sill. In such circumstances, in order to further enhance engagement, these rails of the contact edge may have a broader proportion in comparison to other parts. it will be understood that broader engagement between the contact edge and the window sill will enhance resistance to sideways movement, it will also be understood that broader engagement will generally extend the life of the contact edge in terms of wear over a wider area with the contact edge.

Although it is advantageous for the contact edge to extend along the whole length of the rail, it will be understood that it is also feasible to provide that a lesser portion of the rail length have a contact edge for engagement with a window sill. In such circumstances, it may be cheaper to implement ladders in accordance with the present invention or as indicated above, electively replace the elastomeric strip in the contact edge dependent upon the particular window sills colour or type or to allow replacement of the elastomeric strip or allow more convenient installation of shorter lengths of contact edge.

It will be understood that the elastomeric strips may also provide a security feature in that particular colours or the owner's name or other identifying reference may be formed in the elastomeric strip and therefore, if the ladder is stolen, it will be more easily recognised.

Figure 5 illustrates graphically use of a ladder in accordance with the present invention. Thus, the ladder 60 rests upon a ground surface 61 at one end and a plastic window sill 62 at or towards its other end. As can be seen it is at this abutment between the ladder 60 and the sill 62 that potential slippage problems occur. Such slippage may be downward but of particular Concern is sideways slewing of the ladder 60 into and out of the plane of figure 6. In accordance with the present invention a contact edge 63 is secured to the ladder 60 in order to prevent this sideways slippage.

With a stable ladder 60 it will be appreciated that a window cleaner can ascend the ladder 60 with more confidence and more readily be able to act to either side of the ladder 60 in cleaning a window 64. More particular advantage with regard to window cleaners is that stability is achieved without requiring use of stabilisers or other mechanisms so that the ladder 60 can be rapidly moved between locations to allow the window cleaner access to elevated Windows 64.

Modifications and alterations to the embodiment of the present invention described above will be appreciated by those skilled in the art.

Thus, for example, as indicated those portions of the rail expected to be in contact with a window sill may have an elastomeric strip to form the contact edge which is reinforced or altered in terms of ribbing or material type in order to enhance engagement or wearability compared to other parts of the contact edge. In such circumstances, base engagement with the window sill will be provided at all positions along the rail with the contact edge extending along the whole length of that rail but at the expected portions of the rail generally in contact with the window sill enhanced performance may be achieved.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

Claims 1. A ladder comprising a rail for engaging a plastic window sill,

the rail including a contact edge for engagement in use upon a sill to resist slippage relative to the sill 2. A ladder as claimed in claim 1 wherein the contact edge is formed from a material which locally deforms with a sill in use 3 A ladder as claimed in claim 1 or claim 2 wherein the contact edge comprises an elastomeric material 4 A ladder as claimed in claim 3 wherein the elastomeric material is a rubber strip secured to the rail 5. A ladder as claimed in any preceding claim wherein the contact edge extends along the whole length of the rail 6 A ladder as claimed in any preceding claim wherein the contact edge is ribbed in the direction of the rail 7 A ladder as claimed in any preceding claim wherein the contact edge has a convexed presentation surface for engagement in use with a sill.

8. A ladder as claimed in claim 7 wherein the convexed presentation surface is flattened upon engagement with a sill in use 9 A ladder as claimed in any preceding claim wherein the contact edge is secured in a groove formed in the rail through side shoulder portions of the contact edge being entrapped by a groove.

10. A ladder as claimed in any preceding claim wherein the contact edge is removable from the rail 11 A ladder as claimed in any preceding claim wherein the rail is formed from aluminium 12 A ladder as claimed in any preceding claim wherein the contact edge has a broader portion at positions of the contact edge expected to be in engagement in use upon a sill edge 13. A ladder as claimed in claim 12 wherein the broader portion is displaceable upon the rail for different expected positions for engagement in use upon a sill edge.

14 A ladder as claimed in any preceding claim wherein the ladder comprises two parallel rails with a contact edge secured to each rail.

A ladder substantially as hereinbefore described with reference to the accompanying drawings.

16. A contact edge for a ladder, the edge securable to a rail of a ladder for engagement in use upon a sill edge.

17 An edge as claimed in claim 16 wherein the contact edge is formed from a material which locally deforms with a sill in use.

18 An edge as claimed in claim 16 or claim 17 wherein the contact edge comprises an elastomeric material.

19 An edge as claimed in claim 18 wherein the elastomeric material is a rubber strip secured to the rail An edge as claimed in any of claims 16 to 19 wherein the contact edge has a convexed presentation surface for engagement in use with a sill.

21. An edge as claimed in claim 20 wherein the convexed presentation surface is flattened upon engagement with a sill in use.

22. An edge as claimed in any of claims 16 to 21 wherein the contact edge has a broader portion at positions of the contact edge expected to be in engagement in use upon a sill edge.

23 An edge as claimed in claim 22 wherein the broader portion is displaceable upon the rail for different expected positions for engagement in use upon a sill edge 24 A contact edge for a ladder substantially as hereinbefore described with reference to the accompanying drawings.

Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims