GB2077835A - Extendible steps - Google Patents

Abstract

This invention is a set of extendible steps suitable for mounting on a vehicle or chassis which can be driven or lowered beside an aircraft with the steps collapsed after which the steps can be extended so that passengers can enter or leave the aircraft from the ground. A simple construction with laterally spaced upper and lower flights of treads, and a mid-landing 19 between them can be achieved by having continuous elongate front and rear rails 11, 12 at each side, and identical tread pieces each consisting of a tread 14 and a pair of forwardly or rearwardly extending sides 13 pivoted between the rails. In the upper flight the tread pieces have the treads at the rear, and in the lower flight the tread pieces have the treads at the front. At least one of the continuous elongate rails may carry a stair-lift. <IMAGE>

Description

SPECIFICATION Extendible steps This invention relates to extendible steps for example for use on a van or a manual-or motordriven chassis, at an airport for enabling passengers to enter and leave an aircraft from ground level.

It is an object of the invention to provide a particularly simple construction of such steps with an economy of material.

According to the present invention, extendible steps comprise a pair of laterally spaced side frames each consisting of a front and a rear elongate rail, and a number of tread pieces each comprising a tread, and a pair of forwardly or rearwardly extending sides; the treads being pivoted to the rear rails and the sides being pivoted to the front rails in an upper flight of tread pieces, and the treads being pivoted to the front rails and the sides to the rear rails in a lower flight.

There may be a mid-landing between the two flights pivoted between the front and rear rails at both sides, and a platform pivotally connected at the top pivoted to the rear rails with forwardly extending sides pivoted to the front rails.

The vehicle conveniently carries one or more extensible hydraulic jacks for pivoting the steps upwards about the lower ends of the side frames to cause the rails at each side to separate and thus to extend the steps.

It will be appreciated that each tread piece is pivotally connected in four positions, two at each end, that is with the tread pivoted to the forward or rear rail, and the forwardly or rearwardly extending side pivoted to the other rail. The arrangement is thus very simple and yet an arrangement with a top flight separated from a bottom flight in accordance with International Safety standards can be provided merely by having the tread pieces in the top flight reversed with respect to their positions in the bottom flight.

One advantage is that there is a continuous elongate rail at each side, and that can conveniently be used for an automatic stair lift in which a chair is motor- or manually driven to slide up such a side rail moving above and parallel to the steps so that an invalid does not have to climb the steps.

The invention may be carried into practice in various ways, and one embodiment will now be described by way of example with reference to the accompanying drawings, in which, Figure 1 is a sketch illustrating the principle of the invention; Figure 2 is a side elevation showing the steps in more detail; Figure 3 is a detail of a tread pivot, Figure 4 is a detailed cross section of a lower frame pivot; and Figure 5 is a cross sectional detail of a pivot for a flip-up step at the bottom.

Figure lisa sketch side elevation of the central part of one side of a flight of extendible steps which has a front rail 11 and a rear rail 12 with a number of vertically spaced tread pieces 13 pivotally mounted between the rails.

The tread pieces are all the same and each consists of a transversely extending tread 1 4 and a pair of sides 1 5 one at each end of the tread 14 and extending either forwardly or rearwardly. In an upper flight of tread pieces of which only the lowest is shown in Figure 1 at 16, the tread pieces are mounted on pivots 1 7 which are in line with the treads 14 where they are pivoted to the rear rail 12 and are at the forwardly extending end of the sides 1 5 where they are pivoted to the front rail 11.

1 8 indicates the upper tread pieces 1 3 of a lower flight, and in the lower flight the pivots 1 7 are in line with the treads 14 where they are connected to the front rail 11 and are at the rearwardly extending ends of the sides 1 3 where they are pivoted to the rear rail 12.

A mid-landing 1 9 is positioned vertically midway between the tread pieces 1 6 and 18, and is pivotally connected near its front and rear ends betwen the front and rear rails 11 and 12 at each side.

Figure 2 is a full side elevation of a complete set of extendible steps in the extended position with a flight of lower treads 18 and a flight of upper treads 16, together with a mid-landing 1 9.

The front and rear rails 11 and 12 are of steel of rectangular box section extending throughout the full length of the steps, and one pivotal joint 1 7 is shown in Figure 3, where the section of the rear rail 12 can be seen together with the tread 14 and a bolt 21, and a P.T.F.E. sleeve 22 and washer 23 allowing the tread 14 to rotate about the axis of the bolt 21 with little frictional resistance as the steps are extended and retracted.

At the bottom of the rails 11 and 12, they are pivotted to a horizontai frame member 25 of steel of rectangular hollow section, as shown in Figure 4 where a bolt 26 extends through transverse holes in the members 12 and 25 and is provided with P.T.F.E. cylindrical bushes 27, and a washer 28. At the outer end of the frame member 25 is a pivotally mounted lower tread 29 on a similar pivot pin indicated generally at 31.

The frame members 25 one at each side are fixed to a vehicle (not shown) for driving the steps, when collapsed to an aircraft. A hydraulic actuator (not shown) is pivotted near the front of the vehicle at its lower end and is pivotted to the rear rails 12 near the top so that simply by extending the jack the rear rails 12 are pivotted upwards and the parallelogram linkages formed by the tread pieces, the mid-landing and the front and rear rails pivot together to separate the treads and extend the steps to the position shown in Figure 2. A top landing 33 is pivotally connected at each side to the upper ends of the front and rear rails 11 and 12.

A side rail indicated generally at 34 is located on each front rail 11 by means indicated generally at 35.

The front rail 11 also serves to carry a track for a chair-lift indicated generally at 36. A motor (not shown) on the stair lift 36 enables it to climb up a rack carried by the front rail 11 in front of, and slightky spaced from the treads of the two flights of steps, so that an invalid can ascend without having to climb the steps.

The arrangement is very simple, and economical of material and yet it is strong, can be easily extended, and satisfies the requirements of having lower and upper laterally spaced sets of treads with a mid-landing between them, while yet there are only two continuous elongate rails at each side. An alternative method of driving the stair-lift is by a cable or pulleys at top and bottom with manual means enabling an Attendant to pull the lift up or down a rail or rack.

Claims (9)

1. Extendible steps comprising a pair of laterally spaced side frames each consisting of a front and a rear elongate rail, and a number of tread pieces each comprising a tread and a pair of forwardly or rearwardly extending sides; the treads being pivoted to the rear rails, and the sides being pivoted to the front rails in an upper flight of tread pieces, and the treads being pivoted to the front rails, and the sides to the rear rails in a lower flight.

2. Steps as claimed in Claim 1 including a midlanding between the two flights pivoted between the front and rear rails of both sides.

3. Steps as claimed in either of the preceding claims including a platform pivotally connected to the rear rails at the top with forwardly extending sides pivotted to the front rails.

4. Steps as claimed in any of the preceding claims including a platform pivotally connected to the bottom of the front rails, with rearwardly extending sides pivoted to the rear rails.

5. Steps as claimed in Claim 4 including a lower tread pivotally mounted to the front of the bottom platform.

6. Steps as claimed in any of the preceding claims including a stair-lift arranged to be moved along one of the elongate rails in front of the treads.

7. Steps as claimed in any of the preceding claims in which the tread pieces in the upper and lower flights are the same as each other although they are reversed in the upper flight with respect to the positions they have in the lower flight.

8. Extendible steps as claimed in any of the preceding claims mounted on a vehicle having actuator means for lifting and lowering the steps.

9. Extendible steps constructed and arranged substantially as herein specifically described with reference to the accompanying drawings.