GB2239889A - Self levelling step ladders - Google Patents

Abstract

A set of aluminium step ladders which may be placed down on any uneven or sloping surface whereupon all of the four legs of the step ladder will find their own footing automatically. As shown in Fig 3, two U-shaped frames 10 are hinged together by a slidable hinge, and each includes a steel coil interconnecting telescopic feet 11. When the user climbs the steps the weight of that persons body will cause the sub frame 13 on the front frame to move downwards and so locking the legs in position until that weight is removed whereupon the legs will be free again. The coil in the rear frame is locked by pressure in the coil acting against a brake shoe. <IMAGE>

Description

SELF LEVELLING STEPS AND LADDER'S This invention relates to self levelling steps and ladders.

Step ladders and ladders have become a necessary piece of equipment for the home and at work, they are widely sold into the D.I.Y and professional market throughout the world, The step ladders and ladders available in the present market are all of a fixed leg nature allowing them only to be stable on a flat and level surface.

According to the present invention there is provided a set of self levelling step ladders which allows them to be placed down on any uneven or sloping surface, where upon the design of the step ladders legs enables them to find their own footing on that surface causing the step ladders to remain level and stable.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows in perspective, the step ladders working in complete form on an uneven surface.

Figure 2 illustrates the step ladders from the climbing side on an uneven surface depicting that the steps inner subframe is independent from the step legs.

Figure 3 illustrates a cross section of the step ladders from the climbing side.

Figure 4 illustrates a cross section of the locking system from the climbing side.

Figure 5 illustrates the step ladders movable, locking hinge.

Figure 6 illustrates a cross section of the locking system for the idle side.

Referring to the drawing the step ladder comprises of two leg sections as in figure 1 (10 and 18) connected together by means of the movable locking hinge as in figure 5.

The step ladder sub frame 13 is independent of the master leg section 10 being suspended within this,leg section 10 from the locking system 12 figure 1. This allows the sub frame 13 to move down when weight is put upon it (A person climbing the steps), only being guided by means of the brackets at either side of the base of the sub frame, figure 2 17.

After the sub frame 13 has moved down by means of weight being put upon it, this in turn compresses the spring 16 figure 4 which in turn pushes the rubber plunger 12 down onto the steal coil 14 and so stoping all movement. (locking system).

The two leg sections themselves consist of an outer aluminium tube (round or square) 10 and 18, in which there is two smaller aluminium tubes 11 figure 3 both being connected to a steel coil 14 which slide forward and backwards within the tube 10 figure 3.

Example:- Figure 2 shows the master leg section being placed on an uneven surface causing the right hand facing leg 11 to move in an upwards direction and so the left hand facing leg 11 moves in a downward direction until both find a secure footing, after which when weight is applied to the sub frame 13 , this will operate the locking system 12 as previously ststed.

The idle leg section figure 1, 18 has a slightly different locking system to the master leg section as shown in figure 6.

This system works by means of when weight is applied to the top of the leg section 18 it causes the steel coil 14 to move upwards pushing the tensioned steel cover surrounding the rubber brake shoe 22 figure 6 beyond the rubber brake shoe 23 and so connecting and stoping any movement. (the more weight applied to or upon the leg sections, the greater the braking power.

The movable locking hinge as in figure 5 is permanently fixed to the leg section 18 figure 1 but is allowed to travel upwards and downwards on the master leg section 10 being secured in the desired position by means of the locking handle 20 and 21 figure 5.

Claims (1)

1/ A step ladder and ladder self levelling system comprising two aluminium tubes shaped in the form of an inverted 'U' connected together by means of a movable locking hinge, within each aluminium tube there is two additional aluminium tubes connected together by a steel coil.

2/ A step ladder and ladder self levelling system as claimed in claim 1 wherein the inserted aluminium tubes are free to slide backwards and forwards within the inverted 'U' shaped aluminium tube.

3/ A step ladder and ladder self levelling system as claimed in claim 1 or claim 2 wherein the inserted steel coil is free to slide backwards and forwards within the inverted 'U' shaped aluminium tube.

4/ A step ladder and ladder self levelling system as claimed in claim 2 or claim 3 wherein the weight applied onto the step ladder or ladder is the means for locking the self levelling system with reference to figures 3 and 4 of the accompanying drawings.

5/ A step ladder and ladder self levelling system as claimed in claim 3 or claim 4 wherein there is a movable locking hinge which connects together two inverted 'U' shaped aluminium tubes to form the self levelling 'step ladders' with reference to figure 1 of the accompanying drawings.

CLAIMS ( continusd ) 6/ A step ladder and ladder self levelling system as claimed in claim 4 or claim 5 wherein there is an aluminium sub frame placed within the inverted 'U' shaped aluminium tube, which forms the means for climbing the step ladders with reference to figure 3 of the accompanying drawings.

7/ A step ladder and ladder self levelling system substantially as described herein with reference to figures 1 - 6 of the accompanying drawings.