BACKGROUND OF THE INVENTION In the present state of the art an escalator consists of a series of grooved steps, connected together with two step chains. The steps travel on step guide rails arranged in such a manner as to allow the steps to form a horizontal platform at the entry and exit positions and to open out into a conventional staircase arrangement at about thirty degrees to the horizontal while travelling.

Fixed balustrade skirting panels, one on each side of the steps, are attached to a pair of balustrades. The skirting panels extend from a point above the top of the steps to a point below the top of the steps and the path of travel of the steps is between, and bounded by these skirtings. A small adjustable gap exists between the sides of the step and the skirtings to provide a running clearance on both sides. A nonadjustable gap of about 4mm also exists between adjacent steps.

At the exit end, the steps pass below a threshold plate which extends across and beyond the edges of the steps. This threshold plate is bolted to the top of a truss frame on which the escalator is mounted. A series of combs are located on the leading edge of the threshold plate, the teeth of which extend towards and downward into the grooves of the steps to provide a smooth transition from the moving step to the stationary threshold plate.

Four entrapment points exist in this arrangement and passengers, especially children, can and do become entrapped in these points having either their body parts or clothing entrapped, and often sustain serious injury, including amputation of body parts.

One entrapment point exists between the side of the step risers and the skirting and entrapment can occur when the escalator is travelling in the downwards direction. This is

the most dangerous point of entrapment and exists when the steps are travelling obliquely to the horizontal as clothing, fingers and the like can be caught in the gap between the step risers and the skirting as the step risers are moving relative to the skirting. In the prior art, this area is unprotected as there are no guards to stop entrapment.

Another entrapment point exists between the top of the step and the skirting and entrapment can occur when the escalator travels in the up direction. This is the next most dangerous point of entrapment similar to the above mentioned entrapment point as there is relative movement between the top of the step and the skirting and exists when the steps are travelling obliquely to the horizontal. Similar to the above described entrapment point, there are no guards in the prior art to stop entrapment.

A third entrapment point exists between the rear edge of one step and the riser of the next step. This entrapment point exists when the steps are in transition from oblique to horizontal travel as this is when relative movement of these two edges occurs. Entrapment at this point is partially prevented in the prior art escalators by the interlocking of coarse grooves and ribs on the leading edge of one step and the trailing edge of the adjacent step, however, entrapment can and does still occur. A general clearance of 4mm is provided between the steps in the prior art.

The fourth entrapment point exists at the entry and exit positions between the moving step and the fixed threshold plate and entrapment can occur when the steps are travelling horizontally into the threshold area. The teeth of the comb plate attached to the threshold plate project downward into the step grooves and thus generally prevents entrapment at this point in a fairly satisfactory manner in the prior art escalators.

Various methods have been utilised to prevent passengers from standing too close to the side entrapment points with moderate success. Various safety devices have been used to detect that an object has been drawn into the gap between the steps and the skirting.

However this detection is too late as the accident has already occurred, resulting in passenger entrapment, which can and has caused amputation of body parts, especially with children. Also footwear and other objects can be trapped causing damage to the escalator equipment.

OBJECT OF THE INVENTION The object of the present invention is to provide a safety system for escalators which substantially overcomes or ameliorates the above mentioned problems associated with entrapment points.

DISCLOSURE OF THE INVENTION According to the present invention there is disclosed an escalator system including steps having substantially vertical plate means located at the sides of the steps of the escalator extending upwardly from the horizontal platform of said steps and being adapted to travel with the moving steps, and a balustrade including stationery curtain means, wherein said vertical plate means are adapted to be partially located behind said curtain means as they travel with said steps.

Preferably, the extent of the substantially vertical plate means extending upwardly from the platform of the steps is such that it extends the entire length of the sides of the steps.

Furthermore, the top edge of the substantially vertical plate means are inclined to the horizontal platforms of the steps.

Preferably, the substantially vertical plate means includes a plurality of individual vertical risers associated with each step. Preferably the risers are fixed to the sides of the steps with a portion extending upwardly from the steps and a portion located abutting against the side of the step. When the steps are on the incline, a small gap exists between the edges of the adjacent individual risers and the portion of the gap between the portion above the platform of the step is positioned behind the curtain means and the portion of the gap between the portion below the platform of the step is positioned beside the steps whereby the gap is substantially inaccessible due to the position of the front step risers of the steps. The vertical risers are therefore effectively interlocked with the steps.

Preferably, the risers include an assembly of at least one riser support and a backing plate.

Spacer shims are preferably used to obtain critical spacing between the curtain and risers.

Preferably, the curtain means is fixed to the balustrade decking and is suspended therefrom with its lower edge positioned above the top edges of the steps. The curtain means is preferably formed in sections with lapped joints between adjacent sections.

In a preferred form of the invention, a threshold plate mounting assembly is provided at the entrances and exits of the escalator such that the assembly is suspended from a truss frame of the escalator extending between two frames, a gap being provided between the threshold plate mounting assembly and the truss such that the riser means can pass to the side of the threshold plate mounting assembly while the steps pass beneath it prior to beginning the return path. In the preferred form, the size of the truss frame is modified from the conventional form in that the frame is larger in size at the longitudinal ends of the frame in order that the threshold plate mounting assembly is mounted, and to allow the step riser assemblies can pass around the longitudinal ends.

In the preferred form, the curtain means tapers inwardly to allow the threshold plate mounting assembly to be mounted. Such tapering provides added support to the curtain means, and extra support members are provided.

In the preferred form of the invention, a guide means, in the form of guide rollers, is used to prevent sideways movement of the steps while they are in motion. Preferably, eight guide rollers are used, four on each side, preferably two positioned adjacent the horizontal run area of the escalator and two adjacent the ends of the oblique run area.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described with reference to the drawings in which: Fig. 1 is a partial side schematic sketch view of the escalator safety system of a preferred embodiment; Fig. 2 is an partial side elevation view of similar to Fig. 1 showing detail with respect to the steps and risers;

Fig. 3 is a cutaway sectional view of the system of Fig. 1 showing the relative positions of a step riser assembly and curtain of the system; Fig. 4 is a exploded perspective view of the step riser assembly; Fig. 5 is a cutaway perspective view of the threshold arrangement of the system; Fig. 6 is a schematic plan view of the threshold area of the system; Fig. 7 is schematic sectional side view of the threshold area showing the travel of the steps and risers; Fig. 8 is a cutaway side elevational view of an unassembled curtain of the system; Fig. 9 is a cutaway cross sectional view A-A and C-C of Fig. 8; Fig. 10 is a cutaway cross sectional view B-B and D-D of Fig. 8; Fig. 11 is a cutaway side elevational view of an assembled curtain of the system; Fig. 12 is a plan view of Fig. 11; Fig. 13 is a schematic side elevational view of an elevator truss which is used by the system; and Fig. 14 is a schematic diagram of a step with guide rollers.

BEST MODE OF CARRYING OUT THE INVENTION Firstly it must be understood that this invention is to rectify the problem of entrapment on escalators and an escalator using the design concepts of this invention will also utilise many previously designed escalator principles.

The system 10 of the preferred embodiment includes an appropriately shaped step skirt riser assembly 11 attachable to a step 12 of an escalator 13. The escalator steps 12 are designed such that the step skirt riser assembly 11 is attached to both of the sides 14 of the step 12 below the step platform surface 15 but extends vertically upwardly therefrom. The

step skirt riser assembly 11 should not be confused with the existing balustrade skirting that exists on a conventional escalator.

The step skirt riser assembly 11 includes a shim 16 attachable to the side 14 of the step 12 with a step riser skirt 17 attached thereto. The assembly further includes a riser support backing plate 18 with a shim 19 positioned between the step riser skirt 17 and riser support backing plate 18. The riser support backing plate 18 is used to provide support to the step riser skirt 17 while the shim 16 is used to provide a spacing from each side 14 of the step 12. The spacing is required to provide a small running clearance between the step riser skirt 17 and the side 14 of the next higher step 12, which it overlaps.

The horizontal length of the step skirt riser 17 is substantially the same length as the horizontal length of the step 12 but in the preferred embodiment of this invention the step skirt riser 17 is horizontally offset from the step 12 by a predetermined amount in the direction of the next higher step 12 and projecting far enough beyond the rear edge 20 of the step 12 to pass the leading edge 21 of the next higher step 12. The step skirt riser 17 extends about 225 mm above the rear edge 20 of the step 12 and about 20 mm above the riser edge 21 of the step 12. In effect the step 12 carries a skirt while it travels and now no oblique travel entrapment points exist.

The shape of the step skirt riser 17 in this preferred embodiment is such that it minimises its projection height above the step platform surface 15. Any unnecessary height adversely affects the length of the footprint occupied by the escalator and also the depth of the pit and machine room (not illustrated). In the preferred embodiment of this invention the step skirt riser 17 takes the form of a parallelogram with angles selected to suit the actual arrangement of the escalator and the angle of inclination of the escalator.

The skirt riser backing plate 18 is of similar shape to the step skirt riser 17 and is preferably offset in the opposite direction to the step riser skirt 17. The backing plate 18 is spaced off the step skirt riser 17 a small distance by the shim 19 to provide a running clearance between itself and the step skirt riser 17 of the next lower step 12. In this manner the backing plate 18 overlaps the projecting end of the step skirt riser 17 of the next lower step 12.

The purpose of the backing plate is threefold, to prevent any open gap occurring between adjacent step riser skirts 17, the vertical edges of step riser plates being separated by about 4mm, to provide support for the unattached top edge of the next lower step skirt riser 17, and to provide for very close inter-locking of each step 12 with the adjacent steps 12 so that the steps 12 now form a contiguous length between the two threshold plates 18.

Attached to the balustrade decking of the escalator and extending downwards towards the steps 12 is a curtain 22. The curtain 22 overlaps the step skirt risers 17 but does not extend below the top edge of any step 12 in any position. The curtain 22 is similar in some respects to the conventional balustrade skirting, however, it is attached at its upper side only and is positioned in such a manner as to give a small running clearance from the step skirt riser 17. The step skirt risers 17 travel behind the curtain 22.

It is necessary, for expediency that the curtain 22 is made in sections 23 of convenient length. As the sections cannot be permanently joined or screwed together the joins 24 must ensure a smooth and continuous surface along the curtain 22. The joins 24 of the curtain 13 will be described later.

The effect obtained by attaching the step skirt risers 17 and curtain 22 to the escalator 13 is that there is now no longer a gap beside the travelling step 12 so the entrapment points described above no longer exist. Also as the steps 12 are now interlocked together, the steps 12 are formed into a contiguous length so that no step 12 can move sideways as a single unit. Furthermore, because the outside edges of the steps 12 now form a substantially gap free continuous running surface, guide rollers 25 (Fig. 13) are placed judiciously along the length of the step run and thus prevent, in conjunction with step interlocking, any sideways movement of the system 10. This ensures that the running clearance between the balustrade curtain 22 and the step skirt riser 17 is very small and closely controlled and therefore alignment between comb teeth and step grooves (not illustrated) of the threshold area can also be accurately controlled.

In the preferred embodiment, a minimum four rollers 25 are used on each side of the escalator. One roller 25 is be fitted at each end of the escalator 13 in a horizontal step run

area 26, just ahead of the comb plate entry into which the step grooves fit, in order that the relationship between the comb teeth and step grooves is closely controlled. Two other rollers 25 are fitted, one at each end of the escalator 13 at the end of the oblique run area 27 of the steps to ensure correct step position during the transition phase area 28.

Due to the fact that sideways movement of the steps is now very closely controlled and is minimal, the gap between the steps 12 is reduced to about 1.5 to 2 mm, or less, thus reducing the potential for entrapment at the transition phase area 28.

In a conventional escalator, the threshold plate extends from the top of the truss on one side to the top of the truss on the other side and the steps pass below this plate. This placement of the threshold plate is no longer possible due to the step skirt riser assemblies 11 attached to the steps 12.

As seen in Fig. 13 where a truss 29 is illustrated, the upper horizontal section 30 (dashed lines) of the truss 29 is modified to be higher than a conventional truss. This modification is necessary to support a threshold plate support assembly 31 as seen in Fig. 5 which is modified from the conventional plate.

The threshold plate assembly 31 is an inverted hat shaped assembly attached to the upper horizontal section 30 of the truss 29 and extends downward towards the top of the steps 12.

The threshold plate assembly 31 extends across the top of the steps 12 and provides a small gap between the top of the step 12 and the underside of the assembly 31. A threshold plate 32 is modified so that it does not extend beyond the curtain 22 and is mounted on top of the assembly 31 and a gap 38 is provided between the truss 29 and the vertical side of the inverted hat shaped mounting assembly 31 on each side of the escalator 13 sufficient to allow the step skirt risers 17 to pass through the threshold area.

Furthermore, to allow the steps and skirt risers 17 to pass freely on the return path requires that either the depth of the truss 29 be increased by the height of the step skirt riser 17 or that the steps be opened out to form an inverted staircase arrangement during the return

phase, instead of returning flat in pallet fashion. In the preferred embodiment, the second alternative is used.

As seen in Fig. 7 of the drawings, end 33 of the balustrade curtain 22 is extended, when compared to conventional escalators, to allow passage of the step skirt riser 17 and an end cap 34 is removable to allow easy removal of steps 12 during maintenance. The locus of the peak position of the step skirt riser 17 is also shown.

As seen in the drawings, in the horizontal run area 26 of the steps 12, the top of the steps 12 run closely to and below the bottom of the curtain 22. The curtain 22 has a taper 35, tapering inwardly by the thickness of the sides of the new threshold plate mounting assembly 11 during this phase as seen in Fig. 6. The earlier the tapering starts the more opportunity there is for giving added support for the curtain 22. At this stage the curtain 22 is about 250mm high and supported at the top only. Support members 36 are attached to the top of the truss 30 at this area 26 and the curtain 22 is fixed to these support members 36. The support members 36 are possible at this area 26 due to the provision of the taper 35. The lower portions 37 of the support members 36 are joined. This arrangement now positively prevents the steps 12 moving upwards and colliding with comb and threshold plates 32. At this point the steps 12 are running about 2mm below the lower portion 37 of the support member 36 which means that any upthrust of the steps 32 is limited to 2mm The sections of the curtain 22 cannot be screwed together excepting at the horizontal run area 26 where the threshold support members 36 are located. To overcome this problem the ends of each section of curtain are machined to form a"tapered lap joint". The end is divided into an appropriate even number of equal sections 23. Alternate sections of the edge are machined at 45 degrees from the rear to the front to form a chisel point 39 in that section 23. The remaining sections 23 are machined at 45 degrees from front to rear to form opposite chisel points 39. Corresponding sections on the adjoining curtain section 23 are machined in opposition to the first. These curtain sections 23 then slide into and interlace with each other forming a tapered lap joint 24 and a smooth continuous curtain surface as seen in the drawings.

The inventions as described above provides skirt risers assemblies 11 which ensure the entrapment points between the sides of the steps and the balustrade skirtings are eliminated, thus preventing entrapment, and making the escalator much safer for travelling passengers.

Interlocking of the steps allows minimum running clearance between adjacent parts. The positive guidance rollers placed along the run of the steps, together with the interlocking, ensures continuous accurate tracking of the steps with minimum running clearance from other parts and very accurate alignment of the step grooves and the comb teeth.

The skirt risers assemblies 11 are able to pass through the threshold area as described, while positive means are provided to prevent step upthrust in the threshold area.

In particular, by using the preferred shape of the skirt risers 17 as described, the effect of the riser assemblies 11 on other areas of the escalator 13 is greatly minimised by reducing the vertical height the riser assemblies 11 to the minimum possible. The supported mounting system for the riser assemblies 11 ensures substantially no stability problems.

The addition of the backing plate provides positive support for the unsupported upper edge of the risers 17 of the next lower step 12 thus preventing the top of the risers 17 from moving or bending under sideways horizontal pressure. The provision of the backing plate positively prevents any gap occurring between the vertical edges of adjacent risers, while the interlocking of the steps ensures more accurate and reliable tracking of the steps.

The foregoing describes only one embodiment of the present invention, and modifications obvious to those skilled in the art can be made thereto without departing from the scope of the present invention.