The invention relates to apparatus for opening and closing a platform screen door or gate system, in particular, but not exclusively for a railway system.

The conventional railway station consisting of a raised platform adjacent to the track is essentially the same design as has been used since the beginning of the railway industry in the nineteenth century and is an effective solution to the problem of maximising passenger boarding speed.

However, the basic platform arrangement suffers from several well known problems, such as passengers falling under trains either deliberately or unintentionally and also litter from passengers falling onto the track. Although incidents of people falling under trains are not common, they result in significant disruption to the network and are traumatic incidents for everyone present. The problem of litter on the track has also increased in recent years and can represent a serious health and safety risk on underground or sub-surface systems where the litter will remain in tunnels until it is cleared up.

Platform screen door systems or automated platform gates are well known in the railway industry as one approach of dealing with these problems. Due to the problem of lining up doors on the platform and the train, these systems are usually only installed on lines where the rolling stock is standardised, which in practice is on metro or underground systems, although some dedicated high speed systems are also provided with screens.

As the doors are quite heavy, weighing in some cases over 100kg, and will be operated every few minutes throughout a typical operating day of 18 hours or more, the drive mechanism for the door needs to be very robust and reliable. Increasingly, cost is also a significant factor in determining whether a door system will be installed or not. Most installed platform screen door systems use belt drives to open and close the doors. Due to the special materials used in the belts, which in addition to the requirement of being robust and reliable over a long period, must also be able to operate in high heat and humidity and be insusceptible to fungal attack, the use of belts tends to be a high cost option. This is particularly the case with half height system, often known as gates, where the drive mechanism cannot be located overhead. EP1721802 proposes an alternative drive arrangement comprising a rack and pinion arrangement, wherein the power to the pinion is distributed through a worm gear mechanism.

In some environments space on the platform is particularly limited such that the space required for a normal platform screen door or gate drive system is not available.

The present invention therefore seeks to provide a particularly compact drive system for a platform screen door or gate system.

According to the invention there is provided a platform screen door system comprising a fixed position panel and a door panel, which door panel, in use, is adapted to move between a door open and a door closed position, the door system comprising drive means adapted to control movement of the door, which drive means comprises a flexible toothed belt, which belt is fixed at one end to the door panel and a toothed wheel, which toothed wheel engages with the toothed belt and is adapted to drive the belt thereby moving the door.

In a preferred embodiment, the door is mounted on rollers, which rollers are recessed in the base of the door panel and fixed panel. Preferably, the toothed belt is located within the door panel and the fixed panel.

Preferably, the drive mechanism is housed on a fixed driving panel, the drive mechanism being located above the door or gate, when the door or gate is in the open position. This advantageously permits the drive means to be located at the top of a gate system, which in turn reduces the depth of the gate system and enables a top driven system to be used for a gate system.

Preferably, adjacent pairs of gates are offset from one another, which in turn permits the gates to be spaced more closely to one another.

An exemplary embodiment of the invention will now be described in greater detail with reference to the drawings, in which:

Fig. 1 shows a schematic perspective view of a platform gate system

Fig. 2 shows schematically a front view of the gate system Fig. 3 shows a drive cartridge for the gate system.

Fig. 4 shows a cross section through the gate system

Figure 5 shows a platform screen gate system with adjacent openings

Figure 1 shows a schematic perspective view of a platform gate system 1. The gate system comprises first and second fixed driving panels 2,3, which driving panels are mounted adjacent to an edge of a railway platform and spatially separated from one another. A moveable gate 4,5 is associated with each driving panel and is adapted to be moved between a door open and door closed position (shown). In the door closed position, the gates 4 and 5 abut one another and prevent passage through the gate system by a passenger. In the door open position, passengers are able to embark or disembark from a train (not shown).

The fixed driving panels 2,3 have a width about one third of the width of the associated gate 4,5, and have a solid panel facing away from the platform edge with a upper portion which extends away from the solid panel towards the platform edge and provides a housing for part of the drive mechanism. This is then supported by a strut located behind the solid panel. The fixed driving panels are provided with a hollow profile at its respective lower end where it is mounted on the platform. Rollers 11 are mounted in the hollow profile and the door or gate is adapted to move on these rollers as it is moved between the open and closed positions. A drive cartridge 15 is located at the upper edge of the door to impart drive to the door to move it between the door open and closed positions. The platform gate system is also provided with an obstruction detection system 300.

Figure 2 shows schematically a front view of the gate system showing the gate 4 in the closed position supported on the rollers 11. The rollers 11 are mounted on a floor mounted support structure and rotate about a vertical axis, the surface of the roller engaging with the gate to assist in guiding the gate through the fixed panel 2.

A flexible toothed belt 20 is shown at the upper edge of the gate, which is fixed to the gate 13 and which feeds through the drive cartridge 15, which drive cartridge imparts the drive to the belt 20 to move the gate between the door open and closed positions. A further roller arrangement comprising 3 rollers 21-23 having axes of rotation in the horizontal plane and 3 rollers 25-27 having axes of rotation in the vertical plane is supported on the fixed panel below and adjacent to the upper edge of the gate. These rollers again are again designed to guide the gate through the fixed panel 2. The rollers are arranged such that a pair of rollers arranged successively with axes in the vertical plane are located adjacent to where the gate enters the fixed panel and immediately adjacent to these is a pair of rollers arranged successively with rotational axes in the horizontal plane. A further single roller with an axis in the horizontal plane and a roller with an axis in the vertical plane are located at the opposite side of the fixed panel adjacent to where the gate exits the fixed panel. The control electronics board 290 for controlling the operation of the doors is also mounted on the fixed panel.

Figure 3 shows schematically a drive cartridge for the gate system comprising a motor 30 adapted to drive a toothed wheel 34, which toothed wheel 34 imparts a drive to the belt to open and close the gate 4. The belt is supported by and driven on pulleys 32, 33, 35, 36, 37 & 38, which are supported within the drive cartridge housing. The belt 15 is attached to the gate 4 at its respective ends and rests on the top of the gate when it is outside the drive cartridge housing. In use, the motor drives the toothed wheel under the control of the electronics board 290 and driving engages with the toothed belt 15. The toothed wheel thereby imparts a drive to the gate, which can be moved between the door open and door closed position.

Figure 4 shows a schematic cross section through the gate system showing fixed driving panel 2 and the profile of the gate 4. The depth of the fixed panel is approximately twice the depth of the gate profile. The gate 4 has open profiles at its respective upper and lower edges. At the lower edge, the profile is adapted to engage with and be supported and guided by the lower roller arrangement 11. At the upper edge , the gate has a profile that is closed on three sides and partially closed on the upper edge. The profile is adapted to engage with and be supported by the upper roller arrangement. The upper edge of the gate is closed by the belt 15, so that in use, the gate is not open and liable to collect dust. The roller arrangement on the drive cartridge describe in figure 3 permits the belt to be raised off the top of the gate as it passes through the fixed panel and so the gate engages with the upper roller arrangement. The drive cartridge is mounted on the underside of the upper edge of the fixed panel 2.

Figure 5 shows a platform screen gate system with adjacent openings with the gates in the closed position. The gate system comprises first, second, third and fourth fixed driving panels 2,3, 52,53 and the associated gates 4,5, 54,55. The driving panels 3 and 52 are separated by a short fixed panel 51. The width of the fixed panel 51 together with the width of the driving panel is approximately equal to the width of the gate. As shown and described with regard to Figure 4, the depth of the fixed panel is approximately twice the depth of the gate profile. This in turn permits the adjacent pairs of gates to be offset from one another, which in turn permits the gates to be spaced more closely to one another. This is important for certain railways where the trains have short door pitches.